Improved Brain Tumor Classification by Sodium MR Imaging: Prediction of IDH Mutation Status and Tumor Progression.

BACKGROUND AND PURPOSE: MR imaging in neuro-oncology is challenging due to inherent ambiguities in proton signal behavior. Sodium-MR imaging may substantially contribute to the characterization of tumors because it reflects the functional status of the sodium-potassium pump and sodium channels. MATERIALS AND METHODS: Sodium-MR imaging data of patients with treatment-naïve glioma WHO grades I-IV (n = 34; mean age, 51.29 ± 17.77 years) were acquired by using a 7T MR system. For acquisition of sodium-MR images, we applied density-adapted 3D radial projection reconstruction pulse sequences. Proton-MR imaging data were acquired by using a 3T whole-body system. RESULTS: We demonstrated that the initial sodium signal of a treatment-naïve brain tumor is a significant predictor of isocitrate dehydrogenase (IDH) mutation status (P < .001). Moreover, independent of this correlation, the Cox proportional hazards model confirmed the sodium signal of treatment-naïve brain tumors as a predictor of progression (P = .003). Compared with the molecular signature of IDH mutation status, information criteria of model comparison revealed that the sodium signal is even superior to IDH in progression prediction. In addition, sodium-MR imaging provides a new approach to noninvasive tumor classification. The sodium signal of contrast-enhancing tumor portions facilitates differentiation among most glioma types (P < .001). CONCLUSIONS: The information of sodium-MR imaging may help to classify neoplasias at an early stage, to reduce invasive tissue characterization such as stereotactic biopsy specimens, and overall to promote improved and individualized patient management in neuro-oncology by novel imaging signatures of brain tumors.

Mesoscopic magnetomechanical hysteresis in a magnetorheological elastomer.

Field-induced magnetostatic interaction in a pair of identical particles made of a magnetically soft ferromagnet is studied. It is shown that due to saturation of the ferromagnet magnetization, this case differs significantly from the (super)paramagnetic one. A numerical solution is given, discussed, and compared with that provided by a simpler model (nonlinear mutual dipoles). We show that for multidomain ferromagnetic particles embedded in an elastomer matrix, as for paramagnetic ones in the same environment, pair clusters may form or break by a hysteresis scenario. However, the magnetization saturation brings in important features to this effect. First, the bistability state and the hysteresis take place only in a limited region of the material parameters of the system. Second, along with the hysteresis jumps occurring under the sole influence of the field, the "latent" hysteresis is possible which realizes only if the action of the field is combined with some additional (nonmagnetic) external factor. The obtained conditions, when used to assess the possibility of clustering in real magnetorheological polymers, infer an important role of mesoscopic magnetomechanical hysteresis for the macroscopic properties of these composites.

Responses of the Human Brain to Mild Dehydration and Rehydration Explored In Vivo by 1H-MR Imaging and Spectroscopy.

BACKGROUND AND PURPOSE: As yet, there are no in vivo data on tissue water changes and associated morphometric changes involved in the osmo-adaptation of normal brains. Our aim was to evaluate osmoadaptive responses of the healthy human brain to osmotic challenges of de- and rehydration by serial measurements of brain volume, tissue fluid, and metabolites. MATERIALS AND METHODS: Serial T1-weighted and (1)H-MR spectroscopy data were acquired in 15 healthy individuals at normohydration, on 12 hours of dehydration, and during 1 hour of oral rehydration. Osmotic challenges were monitored by serum measures, including osmolality and hematocrit. MR imaging data were analyzed by using FreeSurfer and LCModel. RESULTS: On dehydration, serum osmolality increased by 0.67% and brain tissue fluid decreased by 1.63%, on average. MR imaging morphometry demonstrated corresponding decreases of cortical thickness and volumes of the whole brain, cortex, white matter, and hypothalamus/thalamus. These changes reversed during rehydration. Continuous fluid ingestion of 1 L of water for 1 hour within the scanner lowered serum osmolality by 0.96% and increased brain tissue fluid by 0.43%, on average. Concomitantly, cortical thickness and volumes of the whole brain, cortex, white matter, and hypothalamus/thalamus increased. Changes in brain tissue fluid were related to volume changes of the whole brain, the white matter, and hypothalamus/thalamus. Only volume changes of the hypothalamus/thalamus significantly correlated with serum osmolality. CONCLUSIONS: This is the first study simultaneously evaluating changes in brain tissue fluid, metabolites, volume, and cortical thickness. Our results reflect cellular volume regulatory mechanisms at a macroscopic level and emphasize that it is essential to control for hydration levels in studies on brain morphometry and metabolism in order to avoid confounding the findings.

Rapid-onset central motor plasticity in multiple sclerosis.

OBJECTIVE: To study rapid-onset central motor plasticity, and its relationship to motor impairment and CNS injury in patients with multiple sclerosis (MS). METHODS: In this cross-sectional observational study, motor plasticity was examined neurophysiologically and behaviorally in 22 patients with moderately severe (median Expanded Disability Status Scale score 2.5 [0-6]) stable MS and matched healthy controls. First, plasticity was assessed using paired associative stimulation (PAS), a protocol modeling long-term synaptic potentiation in human cortex. PAS combines repetitive electric nerve stimulation with transcranial magnetic stimulation (TMS) of the contralateral motor cortex. Second, motor learning was tested by a force production task. Motor impairment was assessed by functional tests. CNS injury was evaluated by obtaining normalized N-acetyl-aspartate (NAA/Cr) spectra using magnetic resonance spectroscopy and by the corticomuscular latency (CML) to the abductor pollicis brevis muscle as tested by TMS. RESULTS: Patients with MS performed worse than controls in functional motor tests, CMLs were prolonged, and NAA/Cr was decreased. PAS-induced enhancement of corticospinal excitability and training-induced increments of motor performance were comparable between patients with MS and controls. Neither PAS-induced plasticity nor motor learning performance correlated with motor impairment or measures of CNS injury. Patients with high CNS injury and good motor performance did not differ significantly from those with high CNS injury and poor motor performance with respect to PAS-induced plasticity and motor learning success. CONCLUSIONS: Despite motor impairment and CNS injury in patients with multiple sclerosis (MS), rapid-onset motor plasticity is comparable to that in healthy subjects. Compensation of MS-related CNS injury is unlikely to be constrained by insufficient rapid-onset neuroplasticity.

[Neuroradiological imaging in patients with sensorineural hearing loss prior to cochlear implantation]. / Neuroradiologische Diagnostik bei Patienten mit sensorineuralem Hörverlust vor Cochlea-Implantation.

Cochlear implantation (CI) is an established technique for enabling speech perception in patients suffering from severe bilateral sensorineural hearing loss (SNHL). Thorough preoperative radiological assessment is essential for correctly evaluating the indication for surgery and safely performing cochlear implantation. CT and conventional and functional MRI are available for radiological assessment. Therefore, knowledge of the most frequent congenital syndromal, non-syndromal, and acquired malformations of inner ear structures is fundamental. This article provides information about imaging techniques prior to CI and relevant malformations of the inner ear. Safety aspects for patients with a cochlear implant undergoing MR imaging are also discussed.

Sedating effects of Humulus lupulus L. extracts.

It was the aim of the study to check ethanolic and CO2 extracts from Humulus lupulus for sedating activity. Both preparations reduced the spontaneous locomotor activity, increased the ketamine-induced sleeping time and reduced body temperature, confirming a central sedating effect. No indications of anxiolytic activity were found in the elevated plus maze test for any of the test preparations. This sedating activity could be attributed to three categories of constituents of lipophilic hops extracts. Though the alpha-bitter acids proved to the be most active constituents, the beta-bitter acids and the hop oil clearly contributed to the sedating activity of lipophilic Humulus extracts.

Comparison of equivalence between the St. John's wort extract LoHyp-57 and fluoxetine.

In a randomised double-blind comparative trial, the antidepressant efficacy of a daily dose of 800 mg of the St. John's wort extract LoHyp-57 (dry extract of St. John's wort, drug extrakt ratio 5-7:1, solvent, ethanol 60% [w/w]) was shown to be equivalent to that of 20 mg fluoxetine (CAS 54910-89-3) in elderly patients with mild or moderate depressive episodes according to ICD 10 (International Statistical Classification of Diseases and Related Health Problems). Treatment was given for six weeks. 149 out-patients (129 females and 20 males) were included in the intention-to-treat analysis. 72 of these patients were assigned to the ICD 10 diagnostic criterion F32.0 (mild depressive episode), while 77 patients were suffering from moderate depressive episodes, corresponding to F32.1. The principal target criterion was the patient's global score on the HAMILTON Depression Scale (items 1-17). During the six-week course of treatment with LoHyp-57, the HAMILTON global score fell from 16.60 points at entry to 7.91 points, and in the fluoxetine sample it fell from 17.18 to 8.11 points. In the group of patients with mild depressive episodes, the score showed a mean fall from 14.21 to 6.21 points on LoHyp-57, and from 15.21 to 7.46 points on fluoxetine. In patients with moderate depressive episodes, the score showed a mean fall from 18.73 to 9.43 points on LoHyp-57 and from 19.10 to 8.75 points on fluoxetine. The efficacy of both medications was found to be equivalent both in mild and moderate depressive episodes. Both treatment groups showed adverse drug reactions (ADRs). Twelve ADRs with a possible relationship to the study medication were reported during treatment with LoHyp-57. Six patients were prematurely withdrawn from treatment with the study medication for this reason. On fluoxetine 17 ADRs occurred with a possible relationship to the study medication. These led to abandonment of treatment and therefore premature withdrawal from the study in 8 cases.

The two facies of pyrrolizidine alkaloids: the role of the tertiary amine and its N-oxide in chemical defense of insects with acquired plant alkaloids.

Larvae of Creatonotos transiens (Lepidoptera, Arctiidae) and Zonocerus variegatus (Orthoptera, Pyrgomorphidae) ingest 14C-labeled senecionine and its N-oxide with the same efficiency but sequester the two tracers exclusively as N-oxide. Larvae of the non-sequestering Spodoptera littoralis eliminate efficiently the ingested alkaloids. During feeding on the two alkaloidal forms transient levels of senecionine (but not of the N-oxide) are built up in the haemolymph of S. littoralis larvae. Based on these results, senecionine [18O]N-oxide was fed to C. transiens larvae and Z. variegatus adults. The senecionine N-oxide recovered from the haemolymph of the two insects shows an almost complete loss of 18O label, indicating reduction of the orally fed N-oxide in the guts, uptake of the tertiary alkaloid and its re-N-oxidation in the haemolymph. The enzyme responsible for N-oxidation is a soluble mixed function monooxygenase. It was isolated from the haemolymph of the sequestering arctiid Tyria jacobaeae and purified to electrophoretic homogeneity. The enzyme is a flavoprotein with a native Mr of 200000 and a subunit Mr of 51000. It shows a pH optimum at 7.0, has its maximal activity at a temperature of 40-45 degrees C and an isoelectric point at pH 4.9. The reaction is strictly NADPH-dependent (Km 1.3 microM). From 20 pyrrolizidine alkaloids so far tested as substrates, the enyzme N-oxidizes only alkaloids with structural elements which are essential for hepatotoxic and genotoxic pyrrolizidine alkaloids (i.e. 1,2-double bond, esterification of the allylic hydroxyl group, presence of a second free or esterified hydroxyl group at carbon 7). A great variety of related alkaloids and xenobiotics were tested as substrate, none was accepted. The Km values of senecionine, monocrotaline and heliotrine, representing the three main types of pyrrolizidine alkaloids, are 1.3 microM, 12.5 microM and 290 microM, respectively. The novel enzyme was named senecionine N-oxygenase (SNO). The enzyme was partially purified from two other arctiids. The three SNOs show the same general substrate specificity but differ in their affinities towards the main structural types of pyrrolizidine alkaloids. The enzymes from the two generalists (Creatonotos transiens and Arctia caja) display a broader substrate affinity than the enzyme from the specialist (Tyria jacobaeae). The two molecular forms of pyrrolizidine alkaloids, the lipophilic protoxic tertiary amine and its hydrophilic nontoxic N-oxide are discussed in respect to their bioactivation and detoxification in mammals and their role as defensive chemicals in specialized insects. Pyrrolizidine-alkaloid-sequestering insects store the alkaloids as nontoxic N-oxides which are reduced in the guts of any potential insectivore. The lipophilic tertiary alkaloid is absorbed passively and then bioactivated by cytochrome P-450 oxidase.

Implementing nursing case management.

While nursing literature abounds with information on nursing case management (NCM), articles discussing actual NCM implementation problems, particularly in the acute rehabilitation setting, are virtually nonexistent. As hospitals seek ways to combat the economic and quality problems stemming from fragmented care, nursing case management provides a viable approach. Yet, it is imperative that those seeking to implement case management realize the importance of careful planning in avoiding common pitfalls. This article discusses NCM and uses a case analysis approach to illustrate problems commonly encountered in implementing the care delivery model. Recommendations for ensuring a smooth transition from primary nursing to nursing case management are presented.