Locus Coeruleus magnetic resonance imaging: a comparison between native-space and template-space approach

Locus Coeruleus (LC) is the main noradrenergic nucleus of the brain, which is involved in many physiological functions including cognition; its impairment may be crucial in the neurobiology of a variety of brain diseases. Locus Coeruleus-Magnetic Resonance Imaging (LC-MRI) allows to identify in vivo LC in humans. Thus, a variety of research teams have been using LC-MRI to estimate LC integrity in normal aging and in patients affected by neurodegenerative disorders, where LC integrity my work as a biomarker. A number of variations between LC-MRI studies exist, concerning post-acquisition analysis and whether this had been performed within MRI native space or in ad hoc-built MRI template space. Moreover, the reproducibility and reliability of this tool is still to be explored. Therefore, in the present study, we analyzed a group of neurologically healthy, cognitively intact elderly subjects, using both a native space- and a template space-based LC-MRI analysis. We found a good inter-method agreement, particularly considering the LC Contrast Ratio. The template space-based approach provided a higher spatial resolution, lower operator-dependency, and allowed the analysis of LC topography. Our ad hoc-developed LC template showed LC morphological data that were in line with templates published very recently. Remarkably, present data significantly overlapped with a recently published LC "metaMask", that had been obtained by averaging the results of a variety of previous LC-MRI studies. Thus, such a template space-based approach may pave the way to a standardized LC-MRI analysis and to be used in future clinic-anatomical correlations.

Time as a factor during endoscopic assessment of swallowing: relevance in defining the score and severity of swallowing disorders

Time is a parameter of great interest in swallowing and can be considered in different ways to express severity during endoscopic evaluation. The objectives of this study are to evaluate how the severity of this score changes at different times of scoring and the interaction between residue persistence and airway invasion. Two experienced raters blindly evaluated 35 short clips of bolus transit that were recorded during endoscopic evaluations of 16 patients with dysphagia of differing aetiologies. The pooling score (p-score) and the Penetration Aspiration Scale (PAS) were detected after the first swallowing (T1) and after the fifth dry swallow (T5). For each task, the time needed to complete the clearing of the bolus (total time: TT) was blindly determined by the two raters and compared with the Functional Oral Intake Scale (FOIS) and Dysphagia Outcome and Severity Scale (DOSS) scales, previously detected.The inter-rater agreement between the 2 raters in scoring the p-score and PAS was good (ICC > 0.800) for T1 vs T1 and T1 vs T5, and in determining TT for each consistency (ICC > 0.9), with a Spearman’s Rho > 0.70 and > 0.90 respectively. A statistical correlation of the p-score total, TT and consistency with FOIS and DOSS was found. The p-score showed a good trade-off between sensitivity and specificity compared with the PAS aspiration and penetration scores. The time of scoring (T1 vs T5) is relevant in detecting severity of dysphagia during endoscopic evaluation. The time spent to clear residue is a useful parameter and is correlated with severity of dysphagia expressed by the p-score and with functional swallowing status in dysphagic patients. The p-score is correlated with the PAS score in detecting airway invasion.

Comparison of electroglottographic variability index in euphonic and pathological voice

In a recent study we introduced a new approach for analysis of the electroglottographic (ECG) signal. This method is based on the evaluation of variation of the EGG signal and its first derivative, through new software developed by the Pisan phoniatric school. This software is designed to extract quantitative indices related to the contacting and decontacting phases of the vocal folds during phonation. The software allows us to study the combined variability of vibration amplitude and velocity (i.e. the first derivative of the EGG signal). Pathological voices show a much more variable EGG signal compared to normal voices, since cordal vibration is made irregular due to the presence of glottis plane pathologies. With the aim of demonstrating the differences between normal and pathological voices relevant to combined vibration amplitude and velocity variability, we have introduced a new quantitative parameter named “variability index, VI”. We studied 95 subjects (35 normal and 60 with pathological voice); among pathologic subjects, 15 showed functional dysphonia and 45 showed organic dysphonia. Subjects affected by organic dysphonia presented: 15 bilateral vocal nodules, 15 unilateral polyps and 15 unilateral cysts. All subjects were studied with videolaryngostroboscopy; electro-acoustic parameters of the voice were analysed with the KayPENTAX CSL (Model 4500) system. The EGG signal was recorded using KAY Model 6103 connected to the CSL system. The new software for the analysis of the EGG signal allows us to obtain not only a VI total value relevant to variability during all the recording, but also partial VI values relevant to the different glottis cycle phases. In fact, plotting the amplitude variation and its first derivative on a Lissajous graph, it is possible to divide the whole glottis cycle into four phases (each represented by four quadrants on the graph): the initial vocal folds contacting activity (VI-Q1), the last phase of vocal folds contacting (VI-Q2), the first phase of vocal folds decontacting (VI-Q3) and the last phase, up to the complete decontacting of vocal folds (VI-Q4). For each quadrant, it is also possible to work out the percent variability index. By comparing the variability indices in the normal and pathological groups, we obtained the following results: the total VI was significantly higher in the pathological subjects (0.25 vs 0.18; p = 0.01); the absolute value of VI was higher in pathological subjects, although the difference was not significant (VI-Q2, 0.041 vs 0.029; VI-Q3, 0.065 vs 0.058; VI-Q4, 0.054 vs 0.052). The percent variability in the Q2 quadrant (VI-Q2%) was significantly higher in pathological subjects compared to normal subjects (0.22 vs 0.16) (p = 0.01). The results of this study confirm that our new software for analysis of EGG signal can distinguish normal voice from pathological voice based on the new quantitative parameter VI. Moreover, this study emphasises that the final contact phase of vocal folds is the most representative of the difference between the normal and pathological voice and shows a wider variability in terms of amplitude and vibration velocity. Further studies on larger groups of subjects will be required to confirm these results and assess differences in the EGG signal among the various vocal fold pathologies.

The endoscopic evaluation of the oral phase of swallowing (Oral-FEES, O-FEES): a pilot study of the clinical use of a new procedure

Oral FEES (O-FEES) is an endoscopic procedure conceived to directly visualise the oral phase of swallowing. In the perspective of clinical use, the feasibility, safety and acceptability of O-FEES has been evaluated. Subsequently, the procedure was compared with the radiological gold standard. The acceptability of O-FEES was compared to that of FEES using a 10 point questionnaire submitted to a sample of 52 outpatients complaining of swallowing disorders. Repeated measure analysis of variance (rm-ANOVA) models were used to test the mean difference of acceptability in the same subjects after FEES and O-FEES. Subsequently, another sample of 8 male outpatients underwent a simultaneous O-FEES and videofluoroscopic study (VFSS). The inter-rater reliability using 10 radiological landmarks, compared to O-FEES, was blindly determined between two raters. Inter-rater agreement between the two judges for O-FEES and VFSS scores was assessed with the single score intra-class correlation coefficient (ICC). Differences between FEES and O-FEES answers for each question and among all the items considered overall were statistically significant (rm-ANOVA; F-statistic p < 0.001). The inter-rater agreement concerning endoscopic and radiological evaluations between the two raters showed strong values of intra-class correlation coefficient (ICC) (95% confidence interval): 0.875 (0.373-0.979) and 0.921 (0.542-0.986), respectively. The Bland-Altman test showed a bias of -0.24 (95% limits of agreement; -1.77 to +1.19), which suggests that both methods produced almost identical results. In clinical practice and compared with FEES, O-FEES is a well tolerated and safe procedure. Compared with the radiological gold standard, O-FEES offers reliable information about oral preparation and oral propulsion of the bolus.

All-Optical Reinforcement Learning In Solitonic X-Junctions

Ethology has shown that animal groups or colonies can perform complex calculation distributing simple decision-making processes to the group members. For example ant colonies can optimize the trajectories towards the food by performing both a reinforcement (or a cancellation) of the pheromone traces and a switch from one path to another with stronger pheromone. Such ant’s processes can be implemented in a photonic hardware to reproduce stigmergic signal processing. We present innovative, completely integrated X-junctions realized using solitonic waveguides which can provide both ant’s decision-making processes. The proposed X-junctions can switch from symmetric (50/50) to asymmetric behaviors (80/20) using optical feedbacks, vanishing unused output channels or reinforcing the used ones.

Comparison between videofluoroscopy, fiberoptic endoscopy and scintigraphy for diagnosis of oro-pharyngeal dysphagia

The purpose of this study was to compare videofluoroscopy (VFS), fiberoptic endoscopic evaluation of swallowing (FEES) and oro-pharyngo- oesophageal scintigraphy (OPES) with regards to premature spillage, post-swallowing residue and aspiration to assess the reliability of these tests for detection of oro-pharyngeal dysphagia. Sixty patients affected with dysphagia of various origin were enrolled in the study and submitted to VFS, FEES and OPES using a liquid and semi-solid bolus. As a reference, we used VFS. Both the FEES and the OPES showed good sensitivity with high overall values (≥ 80% and ≥ 90% respectively). The comparison between FEES vs VFS concerning drop before swallowing showed good specificity (84.4% for semi-solids and 86.7% for liquids). In the case of post-swallowing residue, FEES vs VFS revealed good overall validity (75% for semi-solids) with specificity and sensitivity well balanced for the semi-solids. OPES vs. VFS demonstrated good sensitivity (88.6%) and overall validity (76.7%) for liquids. The analysis of FEES vs. VFS for aspiration showed that the overall validity was low (≤ 65%). On the other hand, OPES demonstrated appreciable overall validity (71.7%). VFS, FEES and OPES are capable of detecting oro-pharyngeal dysphagia. FEES gave significant results in the evaluation of post-swallowing residues.

Face morphology: Can it tell us something about body weight and fat?

This paper proposes a method for an automatic extraction of geometric features, related to weight parameters, from 3D facial data acquired with low-cost depth scanners. The novelty of the method relies both on the processing of the 3D facial data and on the definition of the geometric features which are conceptually simple, robust against noise and pose estimation errors, computationally efficient, invariant with respect to rotation, translation, and scale changes. Experimental results show that these measurements are highly correlated with weight, BMI, and neck circumference, and well correlated with waist and hip circumference, which are markers of central obesity. Therefore the proposed method strongly supports the development of interactive, non obtrusive systems able to provide a support for the detection of weight-related problems.

Assessment of radiation protection awareness and knowledge about radiological examination doses among Italian radiographers

Objectives

To evaluate radiation protection basic knowledge and dose assessment for radiological procedures among Italian radiographers

Methods

A validated questionnaire was distributed to 780 participants with balanced demographic characteristics and geographic distribution.

Results

Only 12.1 % of participants attended radiation protection courses on a regular basis. Despite 90 % of radiographers stating to have sufficient awareness of radiation protection issues, most of them underestimated the radiation dose of almost all radiological procedures. About 5 % and 4 % of the participants, respectively, claimed that pelvis magnetic resonance imaging and abdominal ultrasound exposed patients to radiation. On the contrary, 7.0 % of the radiographers stated that mammography does not use ionising radiation. About half of participants believed that radiation-induced cancer is not dependent on age or gender and were not able to differentiate between deterministic and stochastic effects. Young radiographers (with less than 3 years of experience) showed a higher level of knowledge compared with the more experienced radiographers.

Conclusions

There is a substantial need for radiographers to improve their awareness of radiation protection issues and their knowledge of radiological procedures. Specific actions such as regular training courses for both undergraduate and postgraduate students as well as for working radiographers must be considered in order to assure patient safety during radiological examinations.

Main messages

• Radiographers should improve their knowledge on radiation protection issues.

• Only 12.1 % of participants attended radiation protection courses on a regular basis.

• Specific actions must be considered in order to increase knowledge and awareness.

Optimal scaling of the CAST and of SDS Scale in a national sample of adolescents

PURPOSE

Psychometric and screening properties of the Cannabis Abuse Screening Test (CAST) and of the Severity Dependence Scale (SDS) were investigated using DSM-IV diagnoses of cannabis dependence (CD) as external criteria. Performance of the SDS and of the CAST were compared.

METHODS

Cross-sectional European School Survey Project on Alcohol and Other Drugs (ESPAD) was carried out in Italy in 2009. The sample consisted of 5787 Italian adolescents aged 15-19 who reported cannabis last year use. Uni-dimensionality, internal reliability, external validity, and optimal scaling of the 6 items for CAST and 5 items for SDS were performed. The Munich Composite International Diagnostic Interview (M-CIDI) was used as a gold standard for DSM-IV diagnoses, and all outputs were assessed by 10-fold cross validation procedure.

RESULTS

Both scales were uni-dimensional and Cronbach's α was 0.74 for SDS and 0.78 for CAST. High and comparable area under curve (AUC) values indicate a good ability of both scales to discriminate between individuals with and without dependence diagnosis. Based on balanced sensitivity and specificity, the optimal cut-off scores for problematic use disorders were 7 for CAST MCA and 4 for SDS MCA. Both CAST and SDS overestimated CD prevalence.

CONCLUSIONS

The CAST and SDS are equally useful for screening for problematic cannabis use disorders. Both clinical and research applications of the scales are possible.

A virus binding assay for studying the antigenic landscape on intact, native, primary human immunodeficiency virus-type 1

This protocol describes a simple assay that can be used to study the nature of exposure of antigenic epitopes and antigenic relatedness of different intact, native HIV-1 strains. The assay is based on the principle that mAbs coated on microtiter wells bind to epitopes on the surface of intact, native virions. The bound virion is then lysed to release p24, which is then quantitated (pg/ml) to give a measure of the amount of virion bound to the mAb. High p24 levels released after lysis correlate with high level capture of virions by mAbs, and as such, reflect good exposure of the epitope on the virion. Likewise, binding patterns of a specific mAb with different virus strains reveal information on their antigenic relatedness. In establishing this assay, the nature of exposure of antigenic epitopes and the antigenic relatedness of six intact, native HIV-1 virions of clades A, B, C, D, F and G were examined using anti-HIV-1 mAbs directed at epitopes in the V2, V3, CD4bd and C5 of gp120, and in clusters I and II of the gp41 region. Analysis of the binding data shows that mAbs directed at epitopes in the V3, C5 and gp41 Cluster I region bound best to the viruses examined, suggesting that these are the regions most exposed and conserved on intact, native HIV-1 virions of different clades. Epitopes in the V2 and CD4bd of gp120, and in gp41 cluster II, are not exposed on intact, native virions.

Mapping of epitopes exposed on intact human immunodeficiency virus type 1 (HIV-1) virions: a new strategy for studying the immunologic relatedness of HIV-1

To study the antigenic conservation of epitopes of human immunodeficiency virus type 1 (HIV-1) isolates of different clades, the abilities of human anti-HIV-1 gp120 and gp41 monoclonal antibodies (MAbs) to bind to intact HIV-1 virions were determined by a newly developed virus-binding assay. Eighteen human anti-HIV MAbs, which were directed at the V2, V3 loop, CD4-binding domain (CD4bd), C5, or gp41 regions, were used. Nine HIV-1 isolates from clades A, B, D, F, G, and H were used. Microtiter wells were coated with the MAbs, after which virus was added. Bound virus was detected after lysis by testing for p24 antigen with a noncommercial p24 enzyme-linked immunosorbent assay. The anti-V3 MAbs strongly bound the four clade B viruses and viruses from the non-B clades, although binding was weaker and more sporadic with the latter. The degrees of binding by the anti-V3 MAbs to CXCR4- and CCR5-tropic viruses were similar, suggesting that the V3 loops of these two categories of viruses are similarly exposed. The anti-C5 MAbs bound isolates of clades A, B, and D. Only weak and sporadic binding of all the viruses tested with anti-CD4bd, anti-V2, and anti-gp41 MAbs was detected. These results suggest that V3 and C5 structures are shared and well exposed on intact virions of different clades compared to the CD4bd, V2, and gp41 regions.

Role of cellular adhesion molecules in HIV type 1 infection and their impact on virus neutralization

While CD4 and several chemokine receptors are the principal receptors for human immunodeficiency virus type 1 (HIV-1) viruses, other cell membrane proteins also play a role in HIV-1 infection. A large array of host cell-derived membrane proteins, including adhesion molecules, are incorporated into the envelope of HIV-1 virions, and the profile of host cell proteins acquired by the virus depends on the cells used to propagate the virus. The major leukocyte adhesion molecules, such as leukocyte-function associated antigen-1 (LFA-1), intercellular adhesion molecule-1 (ICAM-1), and CD44, retain their biological functions when expressed on the virion surface, and have been shown to increase virus-cell interaction, enhance virus infectivity, and extend the host cell range of the virus. LFA-1 and its ICAM ligands are also necessary for syncytium formation and cell-to-cell transmission of HIV-1. Furthermore, several studies demonstrate that the presence and level of cell-derived adhesion molecules on the surface of HIV-1 virions affect the process by which antibody-mediated virus neutralization occurs and is measured: the level of virus neutralization is influenced by the host cell-derived adhesion molecules present on the virus, and thus, by the type of host cells in which the virus was produced. Adhesion molecules expressed on the target cells used in neutralization assays similarly affect HIV-1 neutralization by virus-specific antibodies. Consistent with these observations is the finding that neutralizing activities of both HIV+ plasma and human anti-gp120 monoclonal antibodies (Mabs) are enhanced by an anti-LFA-1 Mab capable of blocking LFA-1 functions. Hence, LFA-1, ICAM-1, and other cellular adhesion molecules are involved in different stages of HIV-1 infection and profoundly affect HIV-1 neutralization by virus-specific antibodies. These findings illuminate the biology of virus-cell interactions and have significant implications for evaluating candidate HIV vaccines.

Envelope glycoproteins from human immunodeficiency virus types 1 and 2 and simian immunodeficiency virus can use human CCR5 as a coreceptor for viral entry and make direct CD4-dependent interactions with this chemokine receptor

Several members of the chemokine receptor family have recently been identified as coreceptors, with CD4, for entry of human immunodeficiency virus type 1 (HIV-1) into target cells. In this report, we show that the envelope glycoproteins of several strains of HIV-2 and simian immunodeficiency virus (SIV) employ the same chemokine receptors for infection. Envelope glycoproteins from HIV-2 use CCR5 or CXCR4, while those from several strains of SIV use CCR5. Our data indicate also that some viral envelopes can use more than one coreceptor for entry and suggest that some of these coreceptors remain to be identified. To further understand how different envelope molecules use CCR5 as an entry cofactor, we show that soluble purified envelope glycoproteins (SU component) from CCR5-tropic HIV-1, HIV-2, and SIV can compete for binding of iodinated chemokine to CCR5. The competition is dependent on binding of the SU glycoprotein to cell surface CD4 and implies a direct interaction between envelope glycoproteins and CCR5. This interaction is specific since it is not observed with SU glycoprotein from a CXCR4-tropic virus or with a chemokine receptor that is not competent for viral entry (CCR1). For HIV-1, the interaction can be inhibited by antibodies specific for the V3 loop of SU. Soluble CD4 was found to potentiate binding of the HIV-2 ST and SIVmac239 envelope glycoproteins to CCR5, suggesting that a CD4-induced conformational change in SU is required for subsequent binding to CCR5. These data suggest a common fundamental mechanism by which structurally diverse HIV-1, HIV-2, and SIV envelope glycoproteins interact with CD4 and CCR5 to mediate viral entry.

Host cell-dependent alterations in envelope components of human immunodeficiency virus type 1 virions

In addition to gp41 and gp120, an array of cell adhesion molecules is present on the envelope of human immunodeficiency virus type 1 (HIV-1). To examine the role of the host cell in the acquisition of these molecules by virions, both laboratory-adapted and primary isolates were sequentially passaged into different host cells. Viruses obtained from the various host cells were examined for the presence of 10 different cell-derived molecules by a virus binding enzyme-linked immunosorbent assay. Virus progeny raised in peripheral blood mononuclear cells expressed most of the adhesion molecules tested, with the level of LFA-1 being the highest. When viruses were passaged into CEM-SS or SupT1 cells, the expression of most of the adhesion molecules on the virus envelope was lost. In contrast, when viruses were passaged into MT2 cells, the virus progeny bore high levels of LFA-3, ICAM-1, and major histocompatibility complex classes I and II. These studies demonstrate for the first time the host cell dependence of the adhesion molecule profile present on the envelope of primary isolates of HIV-1. The presence of several adhesion molecules that have not previously been identified as components of the envelope of either laboratory or primary isolates is also described. In addition, we show that the adhesion molecule profile of the virions is acquired, or lost, within one passage and is maintained with subsequent passages in the same cell type.

The cytotoxic process of CD4 Th1 clones

Previous studies have demonstrated that murine CD4 Th1 cells lack perforin and use a pathway distinctive from CD8 CTL to express cytotoxicity. Whether the cytotoxic process of Th1 cells can be separated into identifiable stages and how these differences affect this process were determined in this study. We have resolved the cytotoxic process of Th1 clones into three stages identical with those of CD8 CTL, namely, conjugate formation/activation, lethal hit, and effector-independent programming for target DNA fragmentation. By comparing the cytotoxic processes between Th1 clones on Ag-pulsed targets and (PMA+A23187)-activated Th1 clones on unpulsed targets, we have also demonstrated that 1) the requirement of CD4 Th1 cells for de novo synthesis of cytotoxic machinery was partly responsible for the lag time in the induction of target DNA fragmentation by Th1 clones; 2) lethal hit was delivered rapidly; 3) lethal hit under forced contact by centrifugation did not need extracellular Ca2+ and Mg2+; 4) without centrifugation, lethal hit required extracellular Mg2+, but not Ca2+; 5) the average functional half life of the cytotoxic machinery was 54 +/- 24 (n = 4) min. The data demonstrate that the cytotoxic process of Th1 clones uses an activation-dependent cytotoxic machinery to deliver a short-lived, short-ranged, and quick-acting lethal hit to target, which induces a program in target for DNA fragmentation.

The cytotoxic process of CD4 Th1 clones

Previous studies have demonstrated that murine CD4 Th1 cells lack perforin and use a pathway distinctive from CD8 CTL to express cytotoxicity. Whether the cytotoxic process of Th1 cells can be separated into identifiable stages and how these differences affect this process were determined in this study. We have resolved the cytotoxic process of Th1 clones into three stages identical with those of CD8 CTL, namely, conjugate formation/activation, lethal hit, and effector-independent programming for target DNA fragmentation. By comparing the cytotoxic processes between Th1 clones on Ag-pulsed targets and (PMA+A23187)-activated Th1 clones on unpulsed targets, we have also demonstrated that 1) the requirement of CD4 Th1 cells for de novo synthesis of cytotoxic machinery was partly responsible for the lag time in the induction of target DNA fragmentation by Th1 clones; 2) lethal hit was delivered rapidly; 3) lethal hit under forced contact by centrifugation did not need extracellular Ca2+ and Mg2+; 4) without centrifugation, lethal hit required extracellular Mg2+, but not Ca2+; 5) the average functional half life of the cytotoxic machinery was 54 +/- 24 (n = 4) min. The data demonstrate that the cytotoxic process of Th1 clones uses an activation-dependent cytotoxic machinery to deliver a short-lived, short-ranged, and quick-acting lethal hit to target, which induces a program in target for DNA fragmentation.