Brain stem diffusion-weighted imaging lesion score: a potential marker of outcome in acute basilar artery occlusion

BACKGROUND AND PURPOSE

The benefit of recanalization in basilar artery occlusion (BAO) has been established. The baseline extent of brain stem damage may also influence the outcome. We investigated whether a baseline diffusion-weighted imaging (DWI) score may provide additional prognostic value in BAO.

MATERIALS AND METHODS

We analyzed baseline clinical and DWI parameters in consecutive patients treated with endovascular procedures for acute BAO. Brain stem DWI lesions were assessed by using a semiquantitative score based on arterial territory segmentation. Outcome at 3 months was dichotomized according to the modified Rankin Scale (mRS) as favorable (mRS, 0-2) or unfavorable (mRS, 3-6). Spearman rank correlation tests assessed the correlation between DWI and clinical variables. Univariate and multivariate logistic regression analyses were used to identify clinical and MR imaging predictors of outcome.

RESULTS

Twenty-nine patients were included. The brain stem DWI score (median, 3; range, 0-14) was correlated with the baseline National Institutes of Health Stroke Scale (NIHSS) score and the presence and length of coma (r = 0.67, 0.49, and 0.53, respectively; P < .01). Recanalization was achieved in 76%. A higher baseline NIHSS score (P = .02) and brain stem DWI score (P = .03), a lower Glasgow Coma Scale score (P = .04), and the presence of coma (P = .05) were associated with poor outcome in univariate analysis. Multivariate analysis showed that the brain stem DWI score was the only independent baseline predictor for clinical outcome (P = .026).

CONCLUSIONS

Baseline brain stem DWI lesion score is an independent marker of outcome in BAO.

Mechanism of the antioxidant action of silybin and 2,3-dehydrosilybin flavonolignans: a joint experimental and theoretical study

Flavonolignans from silymarin, the standardized plant extract obtained from thistle, exhibit various antioxidant activities, which correlate with the other biological and therapeutic properties of that extract. To highlight the mode of action of flavonolignans as free radical scavengers and antioxidants, 10 flavonolignans, selectively methylated at different positions, were tested in vitro for their capacity to scavenge radicals (DPPH and superoxide) and to inhibit the lipid peroxidation induced on microsome membranes. The results are rationalized on the basis of (i) the oxidation potentials experimentally obtained by cyclic voltammetry and (ii) the theoretical redox properties obtained by quantum-chemical calculations (using a polarizable continuum model (PCM)-density functional theory (DFT) approach) of the ionization potentials and the O-H bond dissociation enthalpies (BDEs) of each OH group of the 10 compounds. We clearly establish the importance of the 3-OH and 20-OH groups as H donors, in the presence of the 2,3 double bond and the catechol moiety in the E-ring, respectively. For silybin derivatives (i.e., in the absence of the 2,3 double bond), secondary mechanisms (i.e., electron transfer (ET) mechanism and adduct formation with radicals) could become more important (or predominant) as the active sites for H atom transfer (HAT) mechanism are much less effective (high BDEs).

Theoretical Investigation of the Formation of a New Series of Antioxidant Depsides from the Radiolysis of Flavonoid Compounds

This paper deals with the formation of a series of antioxidant depsides obtained from flavonoid solutions irradiated with gamma rays. These reactions take place in radiolyzed alcohol solutions, a medium that is very rich in many different highly reactive species and that hosts specific reactions. We focus on the first step of those reactions, i.e., reactivity of the solute (flavonoid) with the alkoxy radicals CH(3)O(*) and CH(3)CH(2)O(*) formed in methanol and ethanol, respectively, and their carbon-centered isomers: the 1-hydroxy-methyl ((*)CH(2)OH) and the 1-hydroxy-ethyl (CH(3)(*)CHOH) radicals. Among the different flavonoid groups of molecules, only flavonols are transformed. To establish the structure-reactivity relationship that explains why the radiolytic transformation occurs only for those compounds, the process is rationalized theoretically, with Density Functional Theory calculations, taking into account the solvent effects by a Polarizable Continuum Model and a microhydrated environment (one or two water molecules surrounding the active center). The first redox reaction, occurring between the flavonol and the reactive species formed upon irradiation of the solvent, is studied in terms of (1) the O-H bond dissociation enthalpy of each OH group of the flavonoids and (2) electron abstraction from the molecule. We conclude that the reaction, initiated preferentially by the alkoxy radicals, first occurs at the 3-OH group of the flavonol. It is then followed by the formation of a peroxyl radical (after molecular oxygen or superoxide addition). The different cascades of reactions, which lead to the formation of depsides via C-ring opening, are discussed on the basis of the corresponding calculated energetic schemes.

Density Functional Theory Study of the Conformational, Electronic, and Antioxidant Properties of Natural Chalcones

Chalcones are natural compounds that are largely distributed in plants, fruits, and vegetables. They belong to the flavonoid group of molecules, and some of them exhibit numerous biological activities. The results of quantum chemical calculations (based on density functional theory, using the B3P86 exchange-correlation potential) are reported for 11 chalcones, in the gas phase and in the presence of an implicit solvent (using the conductor-like polarizable continuum model, C-PCM). These results are discussed in regard to the capacity of these chalcones to scavenge the 2,2-diphenyl-1-pycril-hydrazyl (DPPH) free radical. The O-H bond dissociation enthalpy (BDE) parameter, which is calculated for each OH group, seems to be the best indicator of the anti-radical property of these compounds. This demonstrates the importance of the H atom transfer mechanism to explain their capacity to scavenge the free radicals. The active sites are identified as the 6'-OH group and the 3,4-dihydroxy-catechol. The alpha,beta-double bond is influential in determining the activity.

Reactivity of Chalcones with 1-Hydroxymethyl Radicals

Reactivity of chalcones with reactive species issued from methanol radiolysis was investigated in the absence or presence of dioxygen. Chalcones are natural antioxidants that are present in fruit and vegetables. Their degradation in the radiolysed solutions was followed by HPLC, NMR, FAB-LSIMS mass spectroscopy and analytical TLC in deaerated solution. Among the 18 identified radiolytic compounds, 16 were new. The formation of the radiolytic products was not influenced by A- and B-ring substitutions. To explain the degradation process, we thus suggested that the primary step was an attack of the alpha,beta-double bond by the 1-hydroxymethyl radical, either at C(alpha) or at C(beta). This step was followed by addition, cyclization or bond dissociations. Different chemical pathways were discussed that implicate the reactive species issued from methanol radiolysis. This paper highlights the relative importance of the different radical species, especially the carbon-centered radical, 1-hydroxymethyl (HMR) and the corresponding oxygen-centered isomer. In addition, an interesting unusual role of dioxygen should be noted; indeed, in the presence of dioxygen, degradation of chalcones was inhibited.

Effets à long terme de la chimiothérapie chez 7 patients présentant un gliome de bas grade symptomatique

INTRODUCTION

Whether aggressive treatment or no treatment is the optimal management for low-grade gliomas is controversial. However, symptomatic low-grade gliomas require prompt therapeutic intervention because of neurological impairment, uncontrolled seizures, and deterioration of life quality.

METHODS

We report the long-term follow-up, 71 months, of seven patients treated by procarbazine, lomustine and vincristine (PCV) therapy for a symptomatic low-grade oligodendrogliomatous tumor. The mean age at diagnosis was 47 years, the mean time from first symptoms to initiation of PCV therapy was 62 months (range 15-147).

RESULTS

All patients initially responded favorably, with improvement of the neurological symptoms and radiological response. Chemotherapy was clinically well tolerated, the main side effect being low hematological toxicity. During the follow-up, no progression was observed in two patients. For the five remaining patients, the time to progression after the PCV induction was 56+/-12 months (range 38 to 73). Four of these patients showed favorable response to a second line of treatment.

CONCLUSION

PCV therapy is an interesting therapeutic option for progressively symptomatic low-grade gliomas, even in cases with large tumoral volume. This treatment, of moderate toxicity, improves the quality of life and can result in long-term tumor stabilization.

Radiolytic Transformation of 2,2′,4′-Trihydroxychalcone

Radiolysis of 2,2',4'-trihydroxychalcone, a natural antioxidant present in fruit and vegetables, was performed in ethanol in the absence or in the presence of dioxygen. The degradation process of chalcone was followed in de-aerated solution by HPLC, NMR, FAB-LSIMS mass spectroscopy and analytical TLC. Under anaerobic conditions, six new products (three couples of diastereoisomers) were identified. Four of them kept the chalcone skeleton with OCH(2)CH(3), CH(OH)CH(3) and H substitutions on C(alpha) and C(beta). Thus the target was the alpha-beta double bond on which ethanol radicals were added. The two other compounds were formed in a second stage and exhibited a cyclization between the substituent on C(beta) and the carbonyl group. In the presence of dioxygen, these reactions were prevented and chalcone was protected. This study was the first step toward understanding of the behavior chalcone in irradiated fruits and vegetables.

Prise en charge des gliomes malins découverts au cours d’une grossesse

INTRODUCTION

Glioma is seldom diagnosed during pregnancy. In this situation management presents difficult problems for both neuro-oncologists and obstetricians. We report four cases and discuss the management of this unusual situation.

CASE REPORT

The first patient was admitted to hospital at 29 weeks' gestation because of a generalized seizure and a right hemiparesis. MRI showed a left fronto-insular lesion. A stereotactic biopsy was obtained and revealed an anaplastic oligodendroglioma. With corticosteroids the patient remained stable until cesarean delivery at 36 weeks. In post-partum additional treatment with chemotherapy was started. The second patient was hospitalized at 26 weeks' gestation because of cranial hypertension, right hemiparesis and aphasia. MRI showed an important left fronto-parietal lesion. Partial resection was performed at 28 weeks. Histology revealed a glioblastoma multiforme. With corticosteroids the patient remained stable until cesarean delivery at 33 weeks. In post-partum additional treatment with radiotherapy and chemotherapy was started. The third patient was admitted to the hospital at 12 weeks' gestation because of cranial hypertension. MRI showed a left frontal lesion. A subtotal resection was done at 13 weeks. Histology revealed a glioblastoma multiforme. Two weeks after surgery the patient's neurological condition worsened and in agreement with the patient a therapeutic abortion was decided. Afterwards additional treatment with radiotherapy and chemotherapy was started. The last patient received combined treatment with radiotherapy and chemotherapy for local recurrence of a mesencephalic high-grade glioma. A posteriori it was discovered that the patient was at 4 months' gestation during this treatment. Cesarean delivery was done at 36 weeks. The child was normal at birth and is still in good health 5 years later.

CONCLUSION

The management of gliomas diagnosed during pregnancy should not be different from the standard management of gliomas in young non-pregnant adults. Pregnant women because of their young age can have a long survival. Their pregnancy should not prevent them from receiving the best treatment for their glioma. Treatment will depend upon clinico-radiological presentation, histology, gestational age and the patient's desires. Generally speaking, surgical resection of high-grade gliomas should not be delayed during pregnancy. Progress in anesthesia and neurosurgery have greatly reduced the risks for the foetus. After delivery, if the delay between surgery and delivery is too long it is possible to begin cerebral radiotherapy during pregnancy. After the first trimester of gestation this treatment can be given without any important risks for the child.

Hyperthyroidism and Cerebral Venous Thrombosis

The demonstration of an underlying prothrombotic condition in cerebral venous thrombosis (CVT) may have important practical consequences in terms of prevention. Thyrotoxicosis through a hypercoagulable state may be a predisposing factor for CVT. The authors present the cases of 4 patients who developed CVT and hyperthyroidism. At the acute stage, hyperthyroidism was associated with an increase in factor VIII (FVIII). At follow-up, FVIII level remained increased in 2 patients. Hyperthyroidism may have an impact on FVIII level. Accordingly in patients with hyperthyroidism and neurological symptoms, the diagnosis of CVT should be considered and an exhaustive coagulation screening may be appropriate.

Structure–function relationship for saponin effects on cell cycle arrest and apoptosis in the human 1547 osteosarcoma cells: a molecular modelling approach of natural molecules structurally close to diosgenin

In this paper, eight natural molecules structurally close to diosgenin (five saponins: diosgenin, hecogenin, tigogenin, sarsasapogenin, smilagenin; two steroidal alkaloids: solasodine, solanidine; one sterol: stigmasterol) have been tested for their biological activities on human 1547 osteosarcoma cells. Differences in activity were studied in term of proliferation rate, cell cycle distribution and apoptosis induction. By using molecular modelling, two structural characteristics were calculated: spatial conformation and electron transfer capacity. The second property has been investigated by the HOMO repartition and the corresponding energy. Correlation between the experimental and the theoretical data permit us to highlight the importance of the hetero-sugar moiety and the 5,6-double bond in the biological activity (apoptosis and cell cycle arrest) on the human 1547 cell line. The importance of conformation at C-5 and C-25 carbon atoms was also discussed.

Castanea sativa Mill. leaves as new sources of natural antioxidant: an electronic spin resonance study

The antioxidant potential of Castanea sativa Mill. leaf (sweet chestnut) was explored as a new source of active extracts. The capacity of the different fractions issued from aqueous, methanol, and ethyl acetate extracts to inhibit the stable free radical 2,2-diphenyl-1-pycryl-hydrazyl, superoxide anion, and hydroxyl radical was measured by electronic spin resonance. Their scavenging potential was analyzed versus their amount of phenolic compounds. Among the active fractions, the most effective one was A6, an ethyl acetate fraction, which contained a high level of total phenolic compounds (29.1 g/100 g). Thus, a different extraction procedure was performed to concentrate the active compounds of A6 in the new C. sativa leaf extract (CSLE). Compared to reference antioxidants (quercetin and vitamin E) and standard extracts (Pycnogenol, from French Pinus maritima bark, and grape marc extract), it was observed that A6 and CSLE have high antioxidant potentials, equivalent to at least those of reference compounds.

Clinical and imaging predictors of intracerebral haemorrhage in stroke patients treated with intravenous tissue plasminogen activator

OBJECTIVE

To evaluate clinical, biological, and pretreatment imaging variables for predictors of tissue plasminogen activator (tPA) related intracerebral haemorrhage (ICH) in stroke patients.

METHODS

48 consecutive patients with hemispheric stroke were given intravenous tPA within seven hours of symptom onset, after computed tomography (CT) and magnetic resonance imaging (MRI) of the brain. Baseline diffusion weighted (DWI) and perfusion weighted (PWI) imaging volumes, time to peak, mean transit time, regional cerebral blood flow index, and regional cerebral blood volume were evaluated. The distribution of apparent diffusion coefficient (ADC) values was determined within each DWI lesion.

RESULTS

The symptomatic ICH rate was 8.3% (four of 48); the rate for any ICH was 43.8% (21 of 48). Univariate analysis showed that age, weight, history of hyperlipidaemia, baseline NIHSS score, glucose level, red blood cell count, and lacunar state on MRI were associated with ICH. However, mean 24 hour systolic blood pressure and a hyperdense artery sign on pretreatment CT were the only independent predictors of ICH. Patients with a hyperdense artery sign had larger pretreatment PWI and DWI lesion volumes and a higher NIHSS score. Analysis of the distribution of ADC values within DWI lesions showed that a greater percentage of pixels had lower ADCs (< 400 x 10(-6) mm(2)/s) in patients who experienced ICH than in those who did not.

CONCLUSION

Key clinical and biological variables, pretreatment CT signs, and MRI indices are associated with tPA related intracerebral haemorrhage.

[Delayed post-anoxic leukoencephalopathy]

INTRODUCTION

The onset of post-anoxic encephalopathies can be delayed after the acute hypoxic injury.

CASE REPORT

We present the case of a 45-year-old woman who achieved complete recovery from an episode of hypoxia related to a suicide attempt (ingestion of benzodiazepine). Three weeks later she developed a confusional state with akinetic mutism and parkinsonism. Brain CT-scan showed bilateral hemispheric white matter hypodensities. MRI showed extensive bilateral hyperintensities on T2-weighted and Flair sequences within the hemispheric white matter and the globus pallidus. EEG showed diffuse slow activity. All investigations for leukodystrophies were negative. Brain biopsy showed normal cortex and widespread demyelination with axonal sparing in the underlying white matter. The patient experienced a partial clinical recovery.

CONCLUSION

The clinical course and the results of paraclinic investigations were consistent with the diagnosis of delayed post-anoxic leukoencephalopathy.

Influence of the site of arterial occlusion on multiple baseline hemodynamic MRI parameters and post-thrombolytic recanalization in acute stroke

In this prospective MRI study, we evaluated the impact of the site of occlusion on multiple baseline perfusion parameters and subsequent recanalization in 49 stroke patients who were given intravenous tissue plasminogen activator (tPA). Pretreatment magnetic resonance angiography (MRA) revealed an arterial occlusion in 47 patients: (1) internal carotid artery (ICA) + M1 middle cerebral artery (MCA) occlusion (n=12); (2) M1 MCA occlusion (n=19); (3) M2 MCA, distal branches of the MCA and anterior cerebral artery (ACA) occlusion (n=16). Patients with ICA occlusion had significantly larger DWI, PWI and mismatch lesion volume on pretreatment MRI compared to patients with other sites of occlusion. The differences in cerebral blood flow (CBF) and peak height were significantly higher in patients with ICA occlusion compared to patients with other sites of occlusion (P=0.03 and P=0.04, respectively). Day 1 MRA showed recanalization in 28 patients (60%). The rate of recanalization was significantly different depending on the site of occlusion: 33% in ICA + M1 MCA occlusion, 63% in M1 MCA occlusion and 81% in either M2 MCA, distal branches of the MCA or ACA occlusion (P=0.002). Our data suggest that CBF and peak height are the most relevant MRI parameters to assess the severity of hemodynamic impairment in regard to the site of occlusion.