Casimir-Polder potentials as entanglement probe

We have considered the interaction of a pair of spatially separated two-level atoms with the electromagnetic field in its vacuum state and we have analyzed the amount of entanglement induced between the two atoms by the non local field fluctuations. This has allowed us to characterize the quantum nature of the non local correlations of the electromagnetic field vacuum state as well as to link the induced quantum entanglement with Casimir-Polder potentials.Comment: Published on Europhysics Letters 78 (2007) 3000

Development of a decision support tool to facilitate primary care management of patients with abnormal liver function tests without clinically apparent liver disease [HTA03/38/02]. Abnormal Liver Function Investigations Evaluation (ALFIE)

Liver function tests (LFTs) are routinely performed in primary care, and are often the gateway to further invasive and/or expensive investigations. Little is known of the consequences in people with an initial abnormal liver function (ALF) test in primary care and with no obvious liver disease. Further investigations may be dangerous for the patient and expensive for Health Services. The aims of this study are to determine the natural history of abnormalities in LFTs before overt liver disease presents in the population and identify those who require minimal further investigations with the potential for reduction in NHS costs

Interobserver reliability and diagnostic performance of Chiari II malformation measures in MR imaging—part 2

PURPOSE: Brain MR imaging is essential in the assessment of Chiari II malformation in clinical and research settings concerning spina bifida. However, the interpretation of MR images of the malformation is not always straightforward. Morphometric analyses of the extent of Chiari II malformation may improve the assessment. In an attempt to select appropriate morphometric measures for this purpose, we investigated the interobserver reliability and diagnostic performance of several morphometric measures of Chiari II malformation on MR images. METHODS: Brain MR images of 79 children [26 with open spinal dysraphism, 17 with closed spinal dysraphism, and 36 without spinal dysraphism; mean age 10.6 (SD 3.2; range, 6-16) years] were evaluated. All children had been assessed for Chiari II malformation (defined as cerebellar herniation in combination with open spinal dysraphism; n = 23). Three observers blindly and independently reviewed the MR images for 21 measures of the cerebellum, brainstem, and posterior fossa in three planes. The interobserver reliability was assessed by an agreement index (AI = 1 - RRE) and the diagnostic performance by receiver operating characteristic analyses. RESULTS: Reliability was good for most measures, except for the degree of herniation of the vermis and tonsil. Most values differed statistically significantly between children with and without Chiari II malformation. The measures mamillopontine distance and cerebellar width showed excellent diagnostic performance. CONCLUSIONS: Morphometric measures may reliably quantify the morphological distortions of Chiari II malformation on MR images and provide additional tools to assess the severity of Chiari II malformation in clinical and research settings

Deliberate termination of life of newborns with spina bifida, a critical reappraisal

Objects: Deliberate termination of life of newborns (involuntary euthanasia) with meningomyelocele (MMC) is practiced openly only in the Netherlands. 'Unbearable and hopeless suffering' is the single most cited criterion for this termination, together with the notion that 'there are no other proper medical means to alleviate this suffering'. In this paper, both (and other) statements are questioned, also by putting them in a broader perspective. Methods: First, a historical overview of the treatment of newborns with MMC is presented, concentrating on the question of selection for treatment. Second, a thorough analysis is made of the criteria used for life termination. Third, a case of a newborn with a very severe MMC is presented as a 'reference case'. Conclusion: 'Unbearable and hopeless suffering' cannot be applied to newborns with MMC. They are not 'terminally ill' and do have 'prospects of a future'. In these end-of-life decisions, 'quality of life judgments' should not be applied. When such a newborn is not treated, modern palliative care always will suffice in eliminating possible discomfort. There is no reason whatsoever for active life-termination of these newborns

Magnetic resonance imaging indicators of blood-brain barrier and brain water changes in young rats with kaolin-induced hydrocephalus

<p>Abstract</p> <p>Background</p> <p>Hydrocephalus is associated with enlargement of cerebral ventricles. We hypothesized that magnetic resonance (MR) imaging parameters known to be influenced by tissue water content would change in parallel with ventricle size in young rats and that changes in blood-brain barrier (BBB) permeability would be detected.</p> <p>Methods</p> <p>Hydrocephalus was induced by injection of kaolin into the cisterna magna of 4-week-old rats, which were studied 1 or 3 weeks later. MR was used to measure longitudinal and transverse relaxation times (T1 and T2) and apparent diffusion coefficients in several regions. Brain tissue water content was measured by the wet-dry weight method, and tissue density was measured in Percoll gradient columns. BBB permeability was measured by quantitative imaging of changes on T1-weighted images following injection of gadolinium diethylenetriamine penta-acetate (Gd-DTPA) tracer and microscopically by detection of fluorescent dextran conjugates.</p> <p>Results</p> <p>In nonhydrocephalic rats, water content decreased progressively from age 3 to 7 weeks. T1 and T2 and apparent diffusion coefficients did not exhibit parallel changes and there was no evidence of BBB permeability to tracers. The cerebral ventricles enlarged progressively in the weeks following kaolin injection. In hydrocephalic rats, the dorsal cortex was more dense and the white matter less so, indicating that the increased water content was largely confined to white matter. Hydrocephalus was associated with transient elevation of T1 in gray and white matter and persistent elevation of T2 in white matter. Changes in the apparent diffusion coefficients were significant only in white matter. Ventricle size correlated significantly with dorsal water content, T1, T2, and apparent diffusion coefficients. MR imaging showed evidence of Gd-DTPA leakage in periventricular tissue foci but not diffusely. These correlated with microscopic leak of larger dextran tracers.</p> <p>Conclusions</p> <p>MR characteristics cannot be used as direct surrogates for water content in the immature rat model of hydrocephalus, probably because they are also influenced by other changes in tissue composition that occur during brain maturation. There is no evidence for widespread persistent opening of BBB as a consequence of hydrocephalus in young rats. However, increase in focal BBB permeability suggests that periventricular blood vessels may be disrupted.</p

Periventricular white-matter cysts in a murine model of gram-negative ventriculitis.

Hydrocephalic patients with shunt infections frequently develop multiple cerebrospinal-fluid-density cysts that cause midline shift and life-threatening intracranial hypertension and respond poorly, if at all, to shunt diversion of cerebrospinal fluid. These cysts have been considered to represent multiloculation of the ventricular system by ependymal adhesions and veils resulting from ventriculitis. Studies using an experimental model of E. coli meningitis/ventriculitis in the hy-3 mouse suggest these cysts: (1) develop by the coalescence of lakes of white-matter edema, (2) grow to large size entirely within the periventricular white matter, and (3) cause pseudoloculation of the ventricle by compression from without. The so-called intraventricular septa or "veils" are the ependyma displaced inward by subependymal cysts or sheets of residual pericystic white matter. This finding permits better interpretation of computed tomographic images depicting persistent enlargement of the so-called multiloculations despite functioning ventricular shunt catheters, the multiplicity of cysts, and the white-matter location of these cysts