Disruption of posterior brain functional connectivity and its relation to cognitive impairment in idiopathic REM sleep behavior disorder

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There is a reduced brain posterior functional connectivity in IRBD patients.

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Reduced temporo-parietal connectivity correlates with mental processing slowness.

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Left superior parietal lobule has reduced centrality in IRBD patients.

Background

Resting-state functional MRI has been proposed as a new biomarker of prodromal neurodegenerative disorders, but it has been poorly investigated in the idiopathic form of rapid-eye-movement sleep behavior disorder (IRBD), a clinical harbinger of subsequent synucleinopathy. Particularly, a complex-network approach has not been tested to study brain functional connectivity in IRBD patients.

Objectives

The aim of the current work is to characterize resting-state functional connectivity in IRBD patients using a complex-network approach and to determine its possible relation to cognitive impairment.

Method

Twenty patients with IRBD and 27 matched healthy controls (HC) underwent resting-state functional MRI with a 3T scanner and a comprehensive neuropsychological battery. The functional connectome was studied using threshold-free network-based statistics. Global and local network parameters were calculated based on graph theory and compared between groups. Head motion, age and sex were introduced as covariates in all analyses.

Results

IRBD patients showed reduced cortico-cortical functional connectivity strength in comparison with HC in edges located in posterior regions (p <0.05, FWE corrected). This regional pattern was also shown in an independent analysis comprising posterior areas where a decreased connectivity in 51 edges was found, whereas no significant results were detected when an anterior network was considered (p <0.05, FWE corrected). In the posterior network, the left superior parietal lobule had reduced centrality in IRBD. Functional connectivity strength between left inferior temporal lobe and right superior parietal lobule positively correlated with mental processing speed in IRBD (r = .633; p = .003). No significant correlations were found in the HC group.

Conclusion

: Our findings support the presence of disrupted posterior functional brain connectivity of IRBD patients similar to that found in synucleinopathies. Moreover, connectivity reductions in IRBD were associated with lower performance in mental processing speed domain.

Cerebral infarction of the basal ganglia due to embolism from the heart

We studied 8 patients with cerebral infarction in the deep territory of the middle cerebral artery (MCA). All patients had a definite cardiac source of emboli and no known factors for thrombosis. Mixed sensory and motor deficit was found in all but one patient and CT scan showed larger lesions than usually reported in lacunar infarcts. Contrast enhancement was seen in all cases in which CT scan was performed in the second or third week. It is concluded that embolic infarcts in deep cerebral territory of MCA from a cardiac source are more frequent than previously reported. This diagnosis has to be considered when CT scan demonstrates a deep cerebral infarct.

Radiologic variables of clinical significance in the extraction of impacted mandibular third molars

OBJECTIVE

To determine which radiologic variables have a clinical significance in the extraction of impacted mandibular third molars.

STUDY DESIGN

A prospective study was carried out on 100 consecutive extractions of unilateral impacted mandibular third molars (60 women and 40 men, mean age: 26.27 +/- 10.63 years). Fourteen radiologic variables were ordinally evaluated, establishing their relation to the surgical intervention time. The Kruskal-Wallis test, a multivariant analysis of the principal components, the Pearson correlation coefficient, and logistical regression tests were carried out.

RESULTS

Seven variables (occlusal plane, relation to the second molar, depth, follicle, periodontal ligament width, ramus of the mandible, and angulation) demonstrated a statistically significant relation to the surgical intervention time (Kruskal-Wallis tests, p < 0.007). Two associated variables, depth and periodontal ligament width, showed the most powerful and simple relation to the surgical intervention time (r2 multiple = 0.307, p < 0.001).

CONCLUSION

The model we propose is a tool that may help the general practitioner to establish competence in an extraction of the impacted mandibular third molar by measuring the association of two radiologic variables: depth and periodontal ligament width.

Randomized phase III trial of capecitabine/cisplatin (XP) vs. continuous infusion of 5-FU/cisplatin (FP) as first-line therapy in patients (pts) with advanced gastric cancer (AGC): Efficacy and safety results

LBA4018

Background: The oral fluoropyrimidine capecitabine has proven efficacy and safety in colorectal and breast cancer. Phase II data in AGC suggested that XP would show comparable efficacy to a standard FP regimen, with potential safety and convenience advantages. This phase III study evaluated XP vs. FP in first-line AGC. Methods: Pts with previously untreated measurable AGC received either oral capecitabine (1000mg/m2 bid d1–14) + cisplatin (80mg/m2 i.v. d1) q3w (XP arm) or 5-FU (800mg/m2/d continuous infusion, d1–5) + cisplatin (80mg/m2 i.v. d1) q3w (FP arm). XP requires 1 day per 3 weeks in hospital; FP requires 5 days. Pts were treated until disease progression or unacceptable toxicity. Primary endpoint: non-inferiority (NI) in progression-free survival (PFS), defined as upper limit of 95% CI of hazard ratio (HR) <1.4 (first test) and <1.25 (second test). Results: From Apr 03 to Jan 05, 316 pts were enrolled in 46 centers/13 countries. Arms were well balanced: median age (years, range) XP (56, 26–74), FP (56, 22–73); median Karnofsky PS 80 (range 70–100) in both arms; male/female (%): XP (64/36) FP (69/31). Median no. of cycles was 5 (XP and FP). Median follow-up is 22.1 months. Primary endpoint was met: HR 0.81 (95% CI 0.63–1.04). XP was superior to FP in terms of overall response rate (ORR, RECIST). Efficacy is presented in the table. Most common treatment-related grade 3/4 adverse events (XP vs. FP) were: neutropenia (16 vs. 19%), vomiting (7 vs. 9%), stomatitis (2 vs. 7%), diarrhea (5 vs. 5%), and anemia (5 vs. 3%). Other grade 3/4 events occurred in <5% of pts. The rate of all-grade hand-foot syndrome was low (22 vs. 4%). Conclusions: XP showed highly significant non-inferiority for PFS and significant superiority for ORR vs. FP with similar safety. These findings suggest that capecitabine should become the fluoropyrimidine of choice for AGC, given the efficacy, reduced hospitalization time and simplified regimen.

No significant financial relationships to disclose.

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Pathological description of a non-motor variant of multiple system atrophy

Multiple system atrophy (MSA) is a neurodegenerative disorder that usually presents clinically as a combination of parkinsonism, cerebellar syndrome and autonomic failure. Patients with MSA can present other clinical features, such as inspiratory stridor and rapid eye movement (REM) sleep behaviour disorder (RBD). We report a patient with pathologically confirmed MSA who presented with a longstanding history of stridor, RBD and autonomic disturbances but did not develop overt parkinsonism or cerebellar signs. This case illustrates that MSA may present clinically without its cardinal motor symptoms, and that stridor and RBD may be clues to recognise the disease in a patient with autonomic failure.

Origin of constant loss in ionic conductors

We have analyzed the constant loss contribution to the ac conductivity in the frequency range 10 Hz-1 MHz and temperatures down to 8 K, for two Li ionic conductors, one crystalline (Li(0.18)La(0.61)TiO(3)) and the other glassy (61SiO(2);35Li(2)O.3Al(2)O3.P(2)O(5)). As temperature is increased a crossover is observed from a nearly constant loss to a fractional power law frequency dependence of the ac conductivity. At any fixed frequency omega, this crossover occurs at a temperature T such that omega approximately nu(0)exp(-E(m)/k(B)T), where nu(0) is the attempt frequency and E(m) is identified with the barrier for Li+ ions to leave their wells.

Preparation of highly accessible mordenite coatings on ceramic monoliths at loadings exceeding 50% by weight

A mordenite layer with a high accessibility has been synthesised on cordierite monolith supports; substantial loadings of mordenite were achieved (above 50 wt%) under the synthesis conditions used.

Chronic alcoholic proximal wasting: physiological, morphological and biochemical studies in skeletal muscle

Electromyography, muscle histochemistry and assay of all glycolytic enzymes, phosphorylase, glycogen, carnitine and several mitochondrial marker enzymes in skeletal muscle (vastus lateralis) were carried out in two groups. One group comprised chronic alcoholic patients with prominent proximal wasting, the other was an alcoholic group with normal neuromuscular examination. Biochemical results were compared with data from control groups with normal muscle histology and with non-alcohol related type 2b fibre atrophy. Either 2b atrophy factor or 2b variability coefficient were increased in all wasted alcoholic patients, with normal values in alcoholics without wasting. Electromyography studies were usually normal in proximal muscles, although several patients had mild distal neuropathies. A significant fall in activity of phosphorylase and all glycolytic enzymes was found in wasted alcoholics with reference to normal controls. In the non-ethanolic 2b atrophy group the activity of several glycolytic enzymes was also significantly lower, but for each enzyme the mean activity was not depressed to the same extent as in the wasted alcoholic group. Muscle glycogen, carnitine, and mitochondrial marker enzyme activities (isocitrate dehydrogenase, monoamine oxidase, cytochrome oxidase) were normal in alcoholics with proximal wasting. It is concluded that there is no deficiency of mitochondrial marker enzymes in wasted alcoholics and that a significant depression in glycogenolytic and glycolytic enzyme activity is seen which is explained in part, but probably not fully, by 2b fibre atrophy.

Selective excitation of vibrational states by shaping of light-induced potentials

In this Letter we describe a method for population transfer using intense, ultrafast laser pulses. The selectivity is accomplished by careful shaping of light-induced potentials (LIPs). Creation and control of the LIPs is accomplished by choosing pairs of pulses with proper frequency detunings and time delays. As an example, selective population transfer is demonstrated for a three-state model of the sodium dimer.

Insight into spin transport in oxide heterostructures from interface-resolved magnetic mapping

At interfaces between complex oxides, electronic, orbital and magnetic reconstructions may produce states of matter absent from the materials involved, offering novel possibilities for electronic and spintronic devices. Here we show that magnetic reconstruction has a strong influence on the interfacial spin selectivity, a key parameter controlling spin transport in magnetic tunnel junctions. In epitaxial heterostructures combining layers of antiferromagnetic LaFeO(3) (LFO) and ferromagnetic La(0.7)Sr(0.3)MnO(3) (LSMO), we find that a net magnetic moment is induced in the first few unit planes of LFO near the interface with LSMO. Using X-ray photoemission electron microscopy, we show that the ferromagnetic domain structure of the manganite electrodes is imprinted into the antiferromagnetic tunnel barrier, endowing it with spin selectivity. Finally, we find that the spin arrangement resulting from coexisting ferromagnetic and antiferromagnetic interactions strongly influences the tunnel magnetoresistance of LSMO/LFO/LSMO junctions through competing spin-polarization and spin-filtering effects.

Electronic and magnetic reconstructions in La0.7Sr0.3MnO3/SrTiO3 heterostructures: a case of enhanced interlayer coupling controlled by the interface

We report on the magnetic coupling of La0.7Sr0.3MnO3 layers through SrTiO3 spacers in La0.7Sr0.3MnO3/SrTiO3 epitaxial heterostructures. Combined aberration-corrected microscopy and electron-energy-loss spectroscopy evidence charge transfer to the empty conduction band of the titanate. Ti d electrons interact via superexchange with Mn, giving rise to a Ti magnetic moment as demonstrated by x-ray magnetic circular dichroism. This induced magnetic moment in the SrTiO3 controls the bulk magnetic and transport properties of the superlattices when the titanate layer thickness is below 1 nm.

Feroxyhyte nanoflakes coupled to up-converting carbon nanodots: a highly active, magnetically recoverable, Fenton-like photocatalyst in the visible-NIR range

Magnetic traffic-lights for photocatalysis: a novel nanohybrid combining feroxyhyte nanoflakes and upconverting carbon nanolights extends the activity range towards the near-infrared using inexpensive LED illumination.

Escaping undesired gas-phase chemistry: Microwave-driven selectivity enhancement in heterogeneous catalytic reactors

Research in solid-gas heterogeneous catalytic processes is typically aimed toward optimization of catalyst composition to achieve a higher conversion and, especially, a higher selectivity. However, even with the most selective catalysts, an upper limit is found: Above a certain temperature, gas-phase reactions become important and their effects cannot be neglected. Here, we apply a microwave field to a catalyst-support ensemble capable of direct microwave heating (MWH). We have taken extra precautions to ensure that (i) the solid phase is free from significant hot spots and (ii) an accurate estimation of both solid and gas temperatures is obtained. MWH allows operating with a catalyst that is significantly hotter than the surrounding gas, achieving a high conversion on the catalyst while reducing undesired homogeneous reactions. We demonstrate the concept with the CO₂-mediated oxidative dehydrogenation of isobutane, but it can be applied to any system with significant undesired homogeneous contributions.

Recurrent hypersomnia in two adolescent males with Asperger's syndrome

Two individuals with Asperger's syndrome, a rare pervasive developmental disorder, developed recurrent episodes of hypersomnia and abnormal behavior (Kleine-Levin syndrome) during adolescence. The possible etiological role of developmental structural brain anomalies and the differential diagnosis of recurrent hypersomnia and abnormal behavior in patients with pervasive developmental disorders are discussed.

Titania-coated gold nanorods with expanded photocatalytic response. Enzyme-like glucose oxidation under near-infrared illumination

Gold nanorods coated with a uniform titanium dioxide nanoshell have been prepared and used as glucose-oxidase surrogates. Remarkably, this core-shell photocatalytic nanostructure has been able to induce complete oxidation of glucose at near room temperature (32-34 °C) in a wide range of pH values with the aid of a near-infrared (NIR) irradiation source. In contrast, the uncoated gold nanorods exhibit negligible photo-oxidation response under identical experimental conditions thereby proving the photoactivity of the titania shell towards glucose oxidation. The process takes place via in situ photo-generation of singlet oxygen or hydroxyl radicals as reactive oxidative species (ROS). This underlines the role played by the core nanorods as plasmonic light harvesters in the NIR range and constitutes the first example of a NIR-activated enzyme-like catalyst.

Association of C4B deficiency (C4B*Q0) with erythema nodosum in leprosy

A considerable number of studies have postulated significant associations between susceptibility to the different clinical manifestations of leprosy and the MHC. In this investigation, the association between the MHC class III complement proteins C2, BF, C4A and C4B and leprosy in a patient population of Southern Brazil was studied. A total of 109 non-related leprosy patients was investigated; 73 presented with lepromatous leprosy (LL), 46 of them had the immunopathological reaction of erythema nodosum (ENL), the remaining 36 were tuberculoid, borderline and indeterminate leprosy (TIBL) patients. The control group included 172 healthy individuals matched with the patients according to their ethnic and geographical origin. C2, BF, C4A and C4B allotypes were determined by standard technologies including Western blots for C2 and C4 variant alleles with monoclonal and polyclonal antibodies. Non-expressed ('silent') C4 alleles in hemizygously deficient individuals were estimated semiquantitatively on the basis of the C4A and C4B isotype ratio and by the MASC ('minimal chi-square') method. The results showed a significantly elevated presence of the non-expressed C4B allele (C4B*Q0) in the LL and ENL patient groups in comparison with the controls. The most significant difference was observed in the ENL group when compared with the controls. In addition, all patients who were homozygously C4B-deficient had ENL, and most of them had the BF*F1 allele. The comparison between LL patients with and without ENL also showed a statistically significant difference in the presence of C4B*Q0, indicating that C4B deficiency itself is associated with ENL. The relative risk of LL patients with the C4B*Q0 allele suffering from ENL was 5.3 compared with LL patients without C4B*Q0. Since immune complexes (IC) are considered to be the pathogenic cause of ENL, our findings indicate that C4B deficiency may play an important role in the abnormal immune response against Mycobacterium leprae and in the lack of IC clearance, leading to ENL reactions. Individuals with this allele seem to be at a higher risk of developing pathological immune reactivity in lepromatous leprosy.