Diffusion-weighted MRI hyperintensity patterns differentiate CJD from other rapid dementias

BACKGROUND

Diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) MRI have high sensitivity and specificity for Creutzfeldt-Jakob disease (CJD). No studies, however, have demonstrated how MRI can distinguish CJD from nonprion causes of rapidly progressive dementia (npRPD). We sought to determine the diagnostic accuracy of MRI for CJD compared to a cohort of npRPD subjects.

METHODS

Two neuroradiologists blinded to diagnosis assessed DWI and FLAIR images in 90 patients with npRPD (n = 29) or prion disease (sporadic CJD [sCJD], n = 48, or genetic prion disease [familial CJD, n = 6, and Gerstmann-Sträussler-Scheinker, n = 7]). Thirty-one gray matter regions per hemisphere were assessed for abnormal hyperintensities. The likelihood of CJD was assessed using our previously published criteria.

RESULTS

Gray matter hyperintensities (DWI > FLAIR) were found in all sCJD cases, with certain regions preferentially involved, but never only in limbic regions, and rarely in the precentral gyrus. In all sCJD cases with basal ganglia or thalamic DWI hyperintensities, there was associated restricted diffusion (apparent diffusion coefficient [ADC] map). This restricted diffusion, however, was not seen in any npRPD cases, in whom isolated limbic hyperintensities (FLAIR > DWI) were common. One reader's sensitivity and specificity for sCJD was 94% and 100%, respectively, the other's was 92% and 72%. After consensus review, the readers' combined MRI sensitivity and specificity for sCJD was 96% and 93%, respectively. Familial CJD had overlapping MRI features with sCJD.

CONCLUSIONS

The pattern of FLAIR/DWI hyperintensity and restricted diffusion can differentiate sCJD from other RPDs with a high sensitivity and specificity. MRI with DWI and ADC should be included in sCJD diagnostic criteria. New sCJD MRI criteria are proposed.

Double-stranded RNAs containing multiple IU pairs are sufficient to suppress interferon induction and apoptosis

Adenosine deaminases acting on RNA (ADARs) catalyze hyperediting of long double-stranded RNAs (dsRNAs), whereby up to 50% of adenosines are converted to inosine (I). Although hyperedited dsRNAs (IU-dsRNAs) have been implicated in various cellular functions, we now provide evidence for another role. We show that IU-dsRNA suppresses the induction of interferon-stimulated genes (ISGs) and apoptosis by poly(IC). Moreover, we show that IU-dsRNA inhibits the activation of interferon regulatory factor 3 (IRF3), which is essential for the induction of ISGs and apoptosis. Finally, we speculate that the inhibition of IRF3 results from specific binding of IU-dsRNA to MDA-5 or RIG-I, both of which are cytosolic sensors for poly(IC). Although our data are consistent with a previous study in which ADAR1 deletion resulted in increased expression of ISGs and apoptosis, we show that IU-dsRNA per se suppresses ISGs and apoptosis. We therefore propose that any IU-dsRNA generated by ADAR1 can inhibit both pathways.

Generalization of the effects of phonological training for anomia using structural equation modelling: a multiple single-case study

Structural Equation Modelling analysis of three longitudinal er-fMRI sessions was used to test the impact of phonological training and of the generalization process on the pattern of brain connectivity during overt picture naming in two chronic anomic patients. Phonological training yielded a positive effect on the trained material. Six months after the training, a generalization of the positive impact on the untrained items was also observed. Connectivity analysis showed that training and generalization effects shared paralleled cortical patterns of functional integration. These findings may represent the neurophysiological correlate of the training-induced cognitive strategies for the compensation of anomia.

Long nuclear-retained non-coding RNAs and allele-specific higher-order chromatin organization at imprinted snoRNA gene arrays

The imprinted Snurf-Snrpn domain, also referred to as the Prader-Willi syndrome region, contains two ∼100-200 kb arrays of repeated small nucleolar (sno)RNAs processed from introns of long, paternally expressed non-protein-coding RNAs whose biogenesis and functions are poorly understood. We provide evidence that C/D snoRNAs do not derive from a single transcript as previously envisaged, but rather from (at least) two independent transcription units. We show that spliced snoRNA host-gene transcripts accumulate near their transcription sites as structurally constrained RNA species that are prevented from diffusing, as well as multiple stable nucleoplasmic RNA foci dispersed in the entire nucleus but not in the nucleolus. Chromatin structure at these repeated arrays displays an outstanding parent-of-origin-specific higher-order organization: the transcriptionally active allele is revealed as extended DNA FISH signals whereas the genetically identical, silent allele is visualized as singlet DNA FISH signals. A similar allele-specific chromatin organization is documented for snoRNA gene arrays at the imprinted Dlk1-Dio3 domain. Our findings have repercussions for understanding the spatial organization of gene expression and the intra-nuclear fate of non-coding RNAs in the context of nuclear architecture.

Supercalifragilisticexpialidocious: how the brain learns words never heard before

Vocabulary acquisition is such a major aspect of language learning in children, but also in adults when learning a foreign language, that a dedicated vocabulary learning device may exist within the language organ. To identify the relevant brain systems, we performed regional cerebral blood flow measurements in normal subjects while they were learning a list of neologisms or a list of word-nonword pairs. Structures implicated in phonological short-term memory (Broca's area, left temporo-parietal junction) were steadily activated during nonwords learning, while the left temporal lobe neocortical and paralimbic structures (parahippocampal region), associated with long-term memory, contributed to learning in a time-dependent manner, with maximal activation at the beginning of the process. The neural system specifically activated when learning new vocabulary was strongly lateralized to the left hemisphere. This evidence refines current models of memory function and supports theories which emphasise the importance of phonological competence in hemispheric dominance for language.

A mobile laminar airflow unit to reduce air bacterial contamination at surgical area in a conventionally ventilated operating theatre

The aim of this study was to evaluate the efficacy of a mobile laminar airflow (LAF) unit in reducing bacterial contamination at the surgical area in an operating theatre supplied with turbulent air ventilation. Bacterial sedimentation was evaluated during 76 clean urological laparotomies; in 34 of these, a mobile LAF unit was added. During each operation, settle plates were placed at four points in the operating theatre (one at the patient area and three at the perimeter), a nitrocellulose membrane was placed on the instrument table and an additional membrane near the wound. During four operations, particle counting was performed to detect particles > or =0.5 microm. Mean bacterial sedimentation on the nitrocellulose membrane on the instrument table was 2730 cfu/m(2)/h under standard ventilation conditions, whereas it decreased significantly to a mean of 305 cfu/m(2)/h when the LAF unit was used, i.e. within the suggested limit for ultraclean operating theatres (P=0.0001). The membrane near the wound showed a bacterial sedimentation of 4031 cfu/m(2)/h without the LAF unit and 1608 cfu/m(2)/h with the unit (P=0.0001). Particle counts also showed a reduction when the LAF unit was used. No significant difference was found at the four points in the operating theatre between samplings performed with, and without, the LAF unit. Use of a mobile LAF unit with turbulent air ventilation can reduce bacterial contamination at the surgical area in high-risk operations (e.g. prosthesis implant).

A pilot study of the reading processes combining reading-related potentials (RRPs) and fMRI

Aim of this work is to describe temporally and spatially the activation of the cerebral areas involved in reading processes by combining fMRI and reading-related potentials (RRPs). RRPs and fMR images were recorded in separate studies during a specifically designed experimental procedure. The protocol consisted of three visual tasks of increasing complexity. In the first two tasks subjects were asked to passively watch at letters and symbols respectively without making any effort in reading or articulating silently them. In the third task subjects were asked to read aloud letters appearing on a screen at a rate of 0.5 Hz. 7 young healthy subjects participated in the experiment. The analysis of RRPs highlighted the following results. During non-alphabetic symbols presentation the amplitude of the potentials was lower in comparison to presentation of letters. Reading aloud generated RRPs of greater amplitude than implicit reading. The analysis of fMRI scans revealed that the visual presentation of both letters and symbols produced similar activation of primary visual areas. Besides these areas, reading aloud activated the motor and pre-motor cortices and the left anterior temporal lobe. The combined analysis of RRPs and fMRI characterizes both temporally and spatially the development of reading processes.

The Von Restorff effect in ageing and Alzheimer’s disease

The purpose of the study was to evaluate the Von Restorff effect in normal ageing and in Alzheimer's disease (AD). A shortened paradigm was administered to three groups of subjects: young volunteers, elderly volunteers and patients with early-stage AD (MMSE>20). Each subject was presented with 25 lists of 10 words each, the target word appearing in double font size. A free recall phase followed the presentation of each list; after completion of the battery, a size recognition test was administered and subjects were inquired regarding the strategy employed and perception of target words. The total number of recalled words differed significantly among the three groups (young volunteers 144.4+/-38.6, elderly volunteers 86.5+/-17.6, patients 44.2+/-14.6). A significant difference in percentage of recall was found between target and non-target words in young (60.0+/-13.8% vs. 45.7%+/-15.0%, p<0.001) and in elderly (31.2+/-11.4% vs. 20.2+/-6.9%, p<0.001) volunteers, but not in patients (10.7+/-6.9% vs. 11.8+/-7.3%). The present study highlights that the Von Restorff effect can be detected in healthy elderly subjects, and that it is significantly reduced in patients in the early stage of AD. On the basis of the findings of the present study it is not possible to disentangle the contribution of visual-perceptual and encoding impairment, both of them potentially contributing to the observed reduction.

ADAR2-mediated editing of RNA substrates in the nucleolus is inhibited by C/D small nucleolar RNAs

Posttranscriptional, site-specific adenosine to inosine (A-to-I) base conversions, designated as RNA editing, play significant roles in generating diversity of gene expression. However, little is known about how and in which cellular compartments RNA editing is controlled. Interestingly, the two enzymes that catalyze RNA editing, adenosine deaminases that act on RNA (ADAR) 1 and 2, have recently been demonstrated to dynamically associate with the nucleolus. Moreover, we have identified a brain-specific small RNA, termed MBII-52, which was predicted to function as a nucleolar C/D RNA, thereby targeting an A-to-I editing site (C-site) within the 5-HT2C serotonin receptor pre-mRNA for 2′-O-methylation. Through the subcellular targeting of minigenes that contain natural editing sites, we show that ADAR2- but not ADAR1-mediated RNA editing occurs in the nucleolus. We also demonstrate that MBII-52 forms a bona fide small nucleolar ribonucleoprotein particle that specifically decreases the efficiency of RNA editing by ADAR2 at the targeted C-site. Our data are consistent with a model in which C/D small nucleolar RNA might play a role in the regulation of RNA editing.

Subcortical nodular heterotopia: a functional MRI and somatosensory evoked potentials study

Subcortical nodular heterotopia (SNH) associated with refractory epilepsy may be surgically treated, and a positive outcome can be expected following the complete excision of the malformed tissue. Recent functional neuroimaging studies have suggested the possible functional relevance of cerebral malformations, and may make it possible to improve presurgical planning, thus allowing extended resections and minimising post-operative deficits. We here report the case of a 19-year-old man with epilepsy and a giant SNH associated with diffused abnormal gyrations of the right temporal-parietal regions. Cortical functional organisation was investigated by means of functional magnetic resonance imaging (MRI) during sensory and motor tasks, and somatosensory evoked potentials. The results revealed enlarged and displaced motor and sensory cortical areas with heterotopic tissue functional activation. The relevance of these findings is discussed in the light of the possible surgical treatment of drug-refractory epilepsy associated with cerebral malformations: surgical treatment based on conventional MRI studies alone, without taking the functional nature of dysplastic tissues into account, may lead to considerable side effects.

[Promoting physical activity in overweight and obese patients: counseling in primary care from Italy (Cesena, 2002--2003)]

Lack of physical activity and obesity represent important public health problems. The objectives of the current study is to evaluate the effects of a counseling intervention (the PACE protocol) conducted by general practitioners and designed to motivate persons who are overweight or obese to increase their levels of physical activity. The counseling was offered 145 patients with a BMI > or =27 who were seen between May 2002 and April 2003 in the offices of 10 general practioners. The intervention, which lasted 3-5 minutes, was conducted during routine visits, based on the Prochaska-DiClemente model of behavioral change. Changes in the motivation of the patients to engage in physical activity and actual changes in levels of activity were measured, as were BMI and abdominal circumference. The median followup was 9 months. Among the 145 eligible patients, 103 (71%) agreed to particpate. Six months following the counselling, there was a significant change in both the motivational status and physical activity of the group, and they experienced significant decreases in BMI and abdominal circumference. Counseling using the PACE model appears to positively influence levels motivation and of physical activity in those patients who agreed to participate. Further studies should be conducted to evaluate the effectiveness of this strategy in other settings and the public health benefits of such counseling.

Identification of 13 novel human modification guide RNAs

Members of the two expanding RNA subclasses termed C/D and H/ACA RNAs guide the 2'-O-methylations and pseudouridylations, respectively, of rRNA and spliceosomal RNAs (snRNAs). Here, we report on the identification of 13 novel human intron-encoded small RNAs (U94-U106) belonging to the two subclasses of modification guides. Seven of them are predicted to direct 2'-O-methylations in rRNA or snRNAs, while the remainder represent novel orphan RNA modification guides. From these, U100, which is exclusively detected in Cajal bodies (CBs), is predicted to direct modification of a U6 snRNA uridine, U(9), which to date has not been found to be pseudouridylated. Hence, within CBs, U100 might function in the folding pathway or other aspects of U6 snRNA metabolism rather than acting as a pseudouridylation guide. U106 C/D snoRNA might also possess an RNA chaperone activity only since its two conserved antisense elements match two rRNA sequences devoid of methylated nucleotides and located remarkably close to each other within the 18S rRNA secondary structure. Finally, we have identified a retrogene for U99 snoRNA located within an intron of the Siat5 gene, supporting the notion that retro-transposition events might have played a substantial role in the mobility and diversification of snoRNA genes during evolution.

Psychological and social aspects in management of Alzheimer’s patients: an inquiry among caregivers

A survey in the cities of Genoa and Savona (Italy) was performed to examine stress levels in caregivers of patients with Alzheimer's disease in the context of a project of the Italian Ministry of Health named Cronos. It offered free anticholinesterase inhibitor therapy to patients who addressed dedicated Neurological Units; in this occasion caregivers could be invited to express the main difficulties encountered in managing demented people during an interview conducted by health personnel of the Neurophysiology Service. Caregivers were mainly women, daughters or spouses, with a medium educational level, retired, housekeepers, employees or teachers; they claimed a lowering of economic standard of living of the family owing to extra expenses for assistance. Satisfaction was expressed towards specialists, while support by general practitioners and other sanitary services was usually lacking and money contribution from the government or territorial services was considered inadequate. From the emotional point of view, caregivers claim loss of free time, friendships and hobbies, and feel isolated in the social context; sometimes the patient's death is thought of as a solution. A strong need for information and support is clearly emerging and any further interventions should take these requirements into consideration.

Restored T-cell activation mechanisms in human tumour-infiltrating lymphocytes from melanomas and colorectal carcinomas after exposure to interleukin-2

We investigated the effects of interleukin-2 (IL-2) exposure on T-cell signal transduction molecules and apoptosis markers in tumour-infiltrating lymphocytes (TIL) isolated from 20 melanoma and 16 colorectal carcinoma metastases and expanded in vitro for therapeutic reinfusion. Before IL-2 culture, TIL showed undetectable or very low levels of T-cell receptor (TCR) epsilon chain, p56(lck), Fas ligand (FasL) and Bax expression, while Bcl-2 values were elevated. Cancer cells were characterised by low or absent Fas and Bcl-2 and high Bax expression. Notably, they also expressed FasL. After 41-48 days of IL-2 culture, TCR epsilon chain and p56(lck) expression of TIL rose to median values of approximately 80 and 30% positive cells, respectively (P<0.001), FasL expression was detected in 45% cells from melanomas (P<0.001) and in 3% from colorectal carcinomas (P=0.09), and Bax-positive cells increased from 17.5 to 70% (P=0.005). Moreover, TCR zeta chain-positive cells were significantly increased from baseline (P=0.001), Bcl-2-positive cells dropped from 50 to 1% (P=0.007) and perforin content was high, while Fas expression was not significantly modified by IL-2 culture. In conclusion, our data suggest that the degree of immunosuppression in TIL from melanomas and colorectal carcinomas is very high, and the apoptosis markers' repertoire of cancer cells resembles that of immune-privileged tissue. Interleukin-2 culture appears to restore lymphocyte activation mechanisms, resulting in consistent FasL expression and perforin production.

Brain functional involvement by perfusion SPECT in systemic sclerosis and Behçet's disease

Involvement of the central nervous system is frequent in systemic immune-mediated diseases, such as systemic lupus erythematosus, Behçet's disease (BD), and systemic sclerosis (SSc). Structural brain examinations, such as computed tomography and magnetic resonance imaging, may be useful in diagnosing and following-up these cerebral syndromes in some cases, but they are more often inconclusive. Single photon emission computed tomography (SPECT) with perfusion tracers is a powerful method that can disclose brain involvement in many clinical situations, even in patients with subtle neurological symptoms. In fact, perfusion tracers can disclose regional hypoperfusion caused by both ischemia due to vascular narrowing and neuronal metabolic derangement due to direct neuronal damage. The latter phenomenon occurs because the blood flow to the brain is strictly regulated by metabolic demands, so that hypometabolism is reflected by hypoperfusion in most instances. SPECT findings in 42 mainly neurologically asymptomatic patients with SSc and in eight mainly neurologically symptomatic patients with BD are reported. SPECT was shown to be very sensitive and disclosed brain functional deficits in approximately half of SSc patients without neurological complaints and in all patients with BD, who had various neurological symptoms but usually inconclusive structural brain examinations.