Changes of EEG spectra and coherence following performance in a cognitive task in Alzheimer's disease.

Electroencephalographic measures combined with cognitive tasks are widely used for the assessment of cognitive and pathophysiological changes in Alzheimer's disease (AD). Instead of the analysis of EEG data obtained during the performance of the task, in this study data recorded in the immediate after-task period were analyzed. It was expected that this period would correspond to the electrophysiological consequences of the cognitive effort. Data of 14 patients with AD (MMS score: 16-24) were compared to that of 10 healthy control subjects. Reverse counting of a fix duration was used as a cognitive task. Changes of relative frequency spectra, and those of inter-and intrahemispheric coherence were analyzed. Relative theta power was significantly higher in AD patients compared to the controls both before and after the task. The performance of the task resulted in an increase of the relative alpha2 band in the AD group, whereas it slightly decreased in the control group. The most prominent coherence differences between AD and controls were found in the alpha1 band, especially for long-range coherence values. Coherence in this frequency band increased in the control group following the task, not seen in the AD group. We conclude that EEG parameters calculated from epochs following the completion of a cognitive task clearly differentiates patients with AD from normal controls. The electrophysiological changes found in AD may correspond to the decrease of functional connectivity of cortical areas and to the malfunctioning of the networks engaged in the cognitive task investigated.     

Cholinergic basal forebrain structures are involved in the mediation of the arousal effect of noradrenaline

Cholinergic basal forebrain structures are implicated in cortical arousal and regulation of the sleep–wake cycle. Cholinergic neurones are innervated by noradrenergic terminals, noradrenaline excites them via alpha‐1 receptors and microinjection of noradrenaline into the basal forebrain enhances wakefulness. However, it is not known to what extent the cholinergic versus non‐cholinergic basal forebrain projection neurones contribute to the arousing effects of noradrenaline. To elucidate the roles of cholinergic basal forebrain structures we administered methoxamine, an alpha‐1‐adrenergic agonist into the basal forebrain, in intact animals and again after selective destruction of the basal forebrain cholinergic cells by 192 IgG‐saporin. In eight male Han–Wistar rats implanted with electroencephalogram/electromyogram electrodes, a microdialysis probe targeted into the basal forebrain was perfused with artificial cerebrospinal fluid for 6 h on a baseline day, and with cerebrospinal fluid in the first and with methoxamine in the second 3‐h period of the subsequent day. The sleep–wake activity was recorded for 24 h on both days. Saporin was then injected into the basal forebrain and 2 weeks later the same experimental schedule (with cerebrospinal fluid and methoxamine) was repeated. In the intact animals, methoxamine exhibited a robust arousing effect and non‐rapid eye movement (NREM) and REM sleep was suppressed. Lesioning of the basal forebrain cholinergic neurones abolished almost completely the NREM sleep‐suppressing effect of methoxamine, whereas the REM sleep‐suppressing effect remained intact. Thus, the basal forebrain cholinergic neurones mediate, at least in part, cortical arousal and non‐REM sleep‐suppression, but they are not involved in the REM sleep‐suppressing effects of noradrenaline.     

The patella and tibial condyle position after combined and after closing wedge high tibial osteotomy

High tibial osteotomy changes the patella and tibial condyle position, which makes the subsequent total knee replacement technically demanding. From 1 January 1993 to 31 December 2000, combined osteotomy [After the first osteotomy made 2 cm distally to the joint line, a bone wedge is removed based laterally. Its tip ends at the center of the tibial condyle (half bone wedge). The distal part of the tibia is placed into the valgus position and the half bone wedge is placed into the gap opened medially.] was performed on 103 knees and closing wedge osteotomy was performed on 47 consecutive knees. Eighty combined (group A) and 41 closing wedge (group B) osteotomy were studied. All knees were assessed radiologically before surgery, in the 10th postoperative week, in the 12th postoperative month and at the time of the final follow-up (in group A—66.15 months, in group B—66.61 months). We examined the change of the femorotibial angle, of the patellar height according to the method of Insall and Salvati, of the tibial slope angle according to the method of Bonnin, of the tibial condylar offset according to the method of Yoshida and of the distance between the lateral tibial plateau and the top of the fibular head. In group A and B, the recurrence of the varus deformity was not noted and valgus alignment did not increase in any case. In group-A, the Insall–Salvati ratio remained unchanged in 65% of knees. The tibial slope angle decreased in both groups. There was correlation between the change of the tibial condylar offset and the angle of the correction in both groups. There was correlation between the change of the distance between the lateral tibial plateau and the top of the fibular head. After combined osteotomy, the transposition of the tibial condyle and the decrease of the distance between the lateral tibial plateau and the top of the fibular head was less than after closing wedge osteotomy, although the average angle of correction was more after combined osteotomy (11.835°), than after closing wedge osteotomy (9.465°). Theoretically, the recurrence of the varus deformity, the increase of the valgus alignment and (in majority of cases) the shortening of the patellar tendon do not compromise the likelihood of successful conversion to the subsequent total knee replacement, either after combined or after closing wedge osteotomy. The combined osteotomy does not lead to considerable transposition of the tibial condyle and to considerable lateral tibial bone loss; therefore, theoretically, the combined osteotomy does not impair the subsequent total knee replacement.     

Iodine-125 Brachytherapy of Brain Stem Tumors

PURPOSE: To report on iodine-125 ((125)I) interstitial irradiation in the treatment of brain stem tumors. PATIENTS AND METHODS: Two patients with brain stem tumors were treated with CT- and image fusion-guided (125)I stereotactic brachytherapy. RESULTS: By March 2003, the patients had been followed up for 47 and 13 months, respectively. In case 1, the tumor volume was 1.98 cm(3) on the control CT, indicating a 65.5% shrinkage as compared to a target volume of 5.73 cm3 at the time of brachytherapy. In case 2, shrinkage was more distinct. After irradiation, the cyst volume was 0.16 cm(3) on the control MRI, indicating a 97.4% shrinkage as compared to a target volume of 6.05 cm(3) at the time of brachytherapy, i. e., the metastasis had virtually disappeared. CONCLUSION: CT- and image fusion-guided (125)I stereotactic brachytherapy can be performed during the biopsy session. The procedure can be well planned dosimetrically and is surgically precise.     

Electrophysiological correlates of visual adaptation to faces and body parts in humans

The existence of facial aftereffects suggests that shape-selective mechanisms at the higher stages of visual object coding -- similarly to the early processing of low-level visual features -- are adaptively recalibrated. Our goal was to uncover the ERP correlates of shape-selective adaptation and to test whether it is also involved in the visual processing of human body parts. We found that prolonged adaptation to female hands -- similarly to adaptation to female faces -- biased the judgements about the subsequently presented hand test stimuli: they were perceived more masculine than in the control conditions. We also showed that these hand aftereffects are size and orientation invariant. However, no aftereffects were found when the adaptor and test stimuli belonged to different categories (i.e. face adaptor and hand test, or vice versa), suggesting that the underlying adaptation mechanisms are category-specific. In accordance with the behavioral results, both adaptation to faces and hands resulted in a strong and category-specific modulation -- reduced amplitude and increased latency -- of the N170 component of ERP responses. Our findings suggest that shape-selective adaptation is a general mechanism of visual object processing and its neural effects are primarily reflected in the N170 component of the ERP responses.     

Silencing the KCNK9 potassium channel (TASK-3) gene disturbs mitochondrial function,causes mitochondrial depolarization,and induces apoptosis of human melanoma cells

TASK-3 (KCNK9 or K_2P9.1) channels are thought to promote proliferation and/or survival of malignantly transformed cells, most likely by increasing their hypoxia tolerance. Based on our previous results that suggested mitochondrial expression of TASK-3 channels, we hypothesized that TASK-3 channels have roles in maintaining mitochondrial activity. In the present work we studied the effect of reduced TASK-3 expression on the mitochondrial function and survival of WM35 and A2058 melanoma cells. TASK-3 knockdown cells had depolarized mitochondrial membrane potential and contained a reduced amount of mitochondrial DNA. Compared to their scrambled shRNA-transfected counterparts, they demonstrated diminished responsiveness to the application of the mitochondrial uncoupler [(3-chlorophenyl)hydrazono]malononitrile (CCCP). These observations indicate impaired mitochondrial function. Further, TASK-3 knockdown cells presented reduced viability, decreased total DNA content, altered cell morphology, and reduced surface area. In contrast to non- and scrambled shRNA-transfected melanoma cell lines, which did not present noteworthy apoptotic activity, almost 50 % of the TASK-3 knockdown cells exhibited strong Annexin-V-specific immunofluorescence signal. Sequestration of cytochrome c from the mitochondria to the cytosol, increased caspase 3 activity, and translocation of the apoptosis-inducing factor from mitochondria to cell nuclei were also demonstrated in TASK-3 knockdown cells. Interference with TASK-3 channel expression, therefore, induces caspase-dependent and -independent apoptosis of melanoma cells, most likely via causing mitochondrial depolarization. Consequently, TASK-3 channels may be legitimate targets of future melanoma therapies.     

Distribution,number, and certain neurochemical identities of infracortical white matter neurons in the brains of three megachiropteran bat species

A large population of infracortical white matter neurons, or white matter interstitial cells (WMICs), are found within the subcortical white matter of the mammalian telencephalon. We examined WMICs in three species of megachiropterans, Megaloglossus woermanni, Casinycteris argynnis, and Rousettus aegyptiacus, using immunohistochemical and stereological techniques. Immunostaining for neuronal nuclear marker (NeuN) revealed substantial numbers of WMICs in each species—M. woermanni 124,496 WMICs, C. argynnis 138,458 WMICs, and the larger brained R. aegyptiacus having an estimated WMIC population of 360,503. To examine the range of inhibitory neurochemical types we used antibodies against parvalbumin, calbindin, calretinin, and neural nitric oxide synthase (nNOS). The calbindin and nNOS immunostained neurons were the most commonly observed, while those immunoreactive for calretinin and parvalbumin were sparse. The proportion of WMICs exhibiting inhibitory neurochemical profiles was ~26%, similar to that observed in previously studied primates. While for the most part the WMIC population in the megachiropterans studied was similar to that observed in other mammals, the one feature that differed was the high proportion of WMICs immunoreactive to calbindin, whereas in primates (macaque monkey, lar gibbon and human) the highest proportion of inhibitory WMICs contain calretinin. Interestingly, there appears to be an allometric scaling of WMIC numbers with brain mass. Further quantitative comparative work across more mammalian species will reveal the developmental and evolutionary trends associated with this infrequently studied neuronal population.     

Improved performance of urinary biomarkers of acute kidney injury in the critically ill by stratification for injury duration and baseline renal function

To better understand the diagnostic and predictive performance of urinary biomarkers of kidney injury, we evaluated γ-glutamyltranspeptidase (GGT), alkaline phosphatase (AP), neutrophil-gelatinase-associated lipocalin (NGAL), cystatin C (CysC), kidney injury molecule-1 (KIM-1), and interleukin-18 (IL-18) in a prospective observational study of 529 patients in 2 general intensive care units (ICUs). Comparisons were made using the area under the receiver operator characteristic curve (AUC) for diagnosis or prediction of acute kidney injury (AKI), dialysis, or death, and reassessed after patient stratification by baseline renal function (estimated glomerular filtration rate, eGFR) and time after renal insult. On ICU entry, no biomarker had an AUC above 0.7 in the diagnosis or prediction of AKI. Several biomarkers (NGAL, CysC, and IL-18) predicted dialysis (AUC over 0.7), and all except KIM-1 predicted death at 7 days (AUC between 0.61 and 0.69). Performance was improved by stratification for eGFR or time or both. With eGFR <60?ml/min, CysC and KIM-1 had AUCs of 0.69 and 0.73, respectively, within 6?h of injury, and between 12 and 36?h, CysC (0.88), NGAL (0.85), and IL-18 (0.94) had utility. With eGFR >60?ml/min, GGT (0.73), CysC (0.68), and NGAL (0.68) had the highest AUCs within 6?h of injury, and between 6 and 12?h, all AUCs except AP were between 0.68 and 0.78. Beyond 12?h, NGAL (0.71) and KIM-1 (0.66) performed best. Thus, the duration of injury and baseline renal function should be considered in evaluating biomarker performance to diagnose AKI.     

Few internal iliac artery aneurysms rupture under 4 cm

Objective

This study investigated the diameter of internal iliac artery (IIA) aneurysms (IIAAs) at the time of rupture to evaluate whether the current threshold diameter for elective repair of 3 cm is reasonable. The prevalence of concomitant aneurysms and results of surgical treatment were also investigated.