Species functional traits and abundance as drivers of multiplex ecological networks: first empirical quantification of inter-layer edge weights.

Many vertebrate species act as both plant pollinators and seed-dispersers, thus interconnecting these processes, particularly on islands. Ecological multilayer networks are a powerful tool to explore interdependencies between processes; however, quantifying the links between species engaging in different types of interactions (i.e. inter-layer edges) remains a great challenge. Here, we empirically measured inter-layer edge weights by quantifying the role of individually marked birds as both pollinators and seed-dispersers of Galápagos plant species over an entire year. Although most species (80%) engaged in both functions, we show that only a small proportion of individuals actually linked the two processes, highlighting the need to further consider intra-specific variability in individuals' functional roles. Furthermore, we found a high variation among species in linking both processes, i.e. some species contribute more than others to the modular organization of the multilayer network. Small and abundant species are particularly important for the cohesion of pollinator seed-dispersal networks, demonstrating the interplay between species traits and neutral processes structuring natural communities.

Structural cortical network reorganization associated with early conversion to multiple sclerosis.

Brain structural covariance networks (SCNs) based on pairwise statistical associations of cortical thickness data across brain areas reflect underlying physical and functional connections between them. SCNs capture the complexity of human brain cortex structure and are disrupted in neurodegenerative conditions. However, the longitudinal assessment of SCN dynamics has not yet been explored, despite its potential to unveil mechanisms underlying neurodegeneration. Here, we evaluated the changes of SCNs over 12 months in patients with a first inflammatory-demyelinating attack of the Central Nervous System and assessed their clinical relevance by comparing SCN dynamics of patients with and without conversion to multiple sclerosis (MS) over one year. All subjects underwent clinical and brain MRI assessments over one year. Brain cortical thicknesses for each subject and time point were used to obtain group-level between-area correlation matrices from which nodal connectivity metrics were obtained. Robust bootstrap-based statistical approaches (allowing sampling with replacement) assessed the significance of longitudinal changes. Patients who converted to MS exhibited significantly greater network connectivity at baseline than non-converters (p = 0.02) and a subsequent connectivity loss over time (p = 0.001-0.02), not observed in non-converters' network. These findings suggest SCN analysis is sensitive to brain tissue changes in early MS, reflecting clinically relevant aspects of the condition. However, this is preliminary work, indicated by the low sample sizes, and its results and conclusions should be treated with caution and confirmed with larger cohorts.

Apparent diffusion coefficient for molecular subtyping of non-gadolinium-enhancing WHO grade II/III glioma: volumetric segmentation versus two-dimensional region of interest analysis.

OBJECTIVES: To investigate if quantitative apparent diffusion coefficient (ADC) measurements can predict genetic subtypes of non-gadolinium-enhancing gliomas, comparing whole tumour against single slice analysis. METHODS: Volumetric T2-derived masks of 44 gliomas were co-registered to ADC maps with ADC mean (ADCmean) calculated. For the slice analysis, two observers placed regions of interest in the largest tumour cross-section. The ratio (ADCratio) between ADCmean in the tumour and normal appearing white matter was calculated for both methods. RESULTS: Isocitrate dehydrogenase (IDH) wild-type gliomas showed the lowest ADC values throughout (p < 0.001). ADCmean in the IDH-mutant 1p19q intact group was significantly higher than in the IDH-mutant 1p19q co-deleted group (p < 0.01). A volumetric ADCmean threshold of 1201 × 10-6 mm2/s identified IDH wild-type with a sensitivity of 83% and a specificity of 86%; a volumetric ADCratio cut-off value of 1.65 provided a sensitivity of 80% and a specificity of 92% (area under the curve (AUC) 0.9-0.94). A slice ADCratio threshold for observer 1 (observer 2) of 1.76 (1.83) provided a sensitivity of 80% (86%), specificity of 91% (100%) and AUC of 0.95 (0.96). The intraclass correlation coefficient was excellent (0.98). CONCLUSIONS: ADC measurements can support the distinction of glioma subtypes. Volumetric and two-dimensional measurements yielded similar results in this study. KEY POINTS: • Diffusion-weighted MRI aids the identification of non-gadolinium-enhancing malignant gliomas • ADC measurements may permit non-gadolinium-enhancing glioma molecular subtyping • IDH wild-type gliomas have lower ADC values than IDH-mutant tumours • Single cross-section and volumetric ADC measurements yielded comparable results in this study.

Evaluating the effects of pollinator-mediated interactions using pollen transfer networks: evidence of widespread facilitation in south Andean plant communities.

Information about the relative importance of competitive or facilitative pollinator-mediated interactions in a multi-species context is limited. We studied interspecific pollen transfer (IPT) networks to evaluate quantity and quality effects of pollinator sharing among plant species on three high-Andean communities at 1600, 1800 and 2000 m a.s.l. To estimate the sign of the effects (positive, neutral or negative), the relation between conspecific and heterospecific pollen deposited on stigmas was analysed with GLMMs. Network analyses showed that communities were characterised by the presence of pollen hub-donors and receptors. We inferred that facilitative and neutral pollinator-mediated interactions among plants prevailed over competition. Thus, the benefits from pollinator sharing seem to outweigh the costs (i.e. heterospecific deposition and conspecific pollen loss). The largest proportion of facilitated species was found at the highest elevation community, suggesting that under unfavourable conditions for the pollination service and at lower plant densities facilitation can be more common.

Significant clinical worsening after natalizumab withdrawal: Predictive factors.

We aimed to single out multiple sclerosis (MS) cases with poor outcome after natalizumab withdrawal and to identify predictive variables. We ascertained 47 withdrawals, and compared their pre- and post-natalizumab periods. We objectively defined significant clinical worsening after natalizumab withdrawal as a 2-step increase in Expanded Disability Status Scale (EDSS). We performed regression models. As a group, post-natalizumab annualized relapse rate (ARR) was lower in the post-natalizumab period, and there were no differences in the mean number of gadolinium (Gd)-enhancing lesions between pre- and post-natalizumab magnetic resonance imaging (MRI). Corticosteroid treatment did not change the outcomes. Eight patients (19%) presented significant clinical worsening after natalizumab withdrawal, which was predicted by a higher baseline EDSS and a 1-step EDSS increase while on natalizumab.

Brain atrophy in natalizumab-treated patients: A 3-year follow-up.

BACKGROUND: A pseudoatrophy effect has been held responsible for the lack of net impact of natalizumab on brain volume outcomes in 2-year trials, but no data are available beyond 24 months. OBJECTIVE: We aimed to investigate brain volume dynamics in natalizumab-treated patients in up to 3 years after therapy initiation with clinical correlations. METHODS: Patients on natalizumab for at least 3 years were clinically assessed 3-monthly. Magnetic resonance imaging scans were performed at baseline and yearly. Brain volume changes were obtained with SIENA. Multivariate models were used to investigate the association between baseline inflammation and changes in brain volume and disability. RESULTS: Sixty-two patients with multiple sclerosis were analysed. Mean age and disease duration were 34.7 (SD: 8.3) and 10.4 (SD: 6.6) years. Presence of gadolinium enhancement at baseline was not associated with Expanded Disability Status Scale changes (p=0.468), but was associated with larger brain volume decreases (p=0.005) in the first (p=0.024) and second year (p=0.019) but not in the third year (p=0.863). Brain volume changes at 12 and 36 months were marginally associated with disability status at month 12 (p=0.094) and 36 (p=0.084), respectively. CONCLUSIONS: Baseline inflammation affects brain volume measures up to 24 months after natalizumab initiation. A marginal association of brain volume changes with disability is present.

Value of NMO-IgG determination at the time of presentation as CIS.

BACKGROUND: Despite the availability of diagnostic criteria, an overlap between neuromyelitis optica (NMO) and multiple sclerosis (MS) exists, particularly in the early stage of the disease. OBJECTIVE: To study the value of NMO-immunoglobulin G (IgG) determination in Caucasian patients with a first demyelinating episode who develop a relapsing form of optic neuritis or myelitis. METHODS: This study was based on a prospectively acquired cohort of patients regarded as having a clinically isolated syndrome (CIS) at the time of presentation. From this cohort, 2 different groups were selected: group 1 (NMO phenotype), consisting of a first attack involving the optic nerve or the spinal cord, and at least a second event affecting either topography, and group 2 (negative control group), consisting of a first attack involving the brainstem or the cerebral hemispheres and at least 1 relapse in any topography. Group 3 was composed of patients with NMO according to the 2006 revised diagnostic criteria. Serum NMO-IgG was determined by indirect immunofluorescence. RESULTS: A total of 3.1 of the group 1 patients were positive for NMO-IgG in comparison to 3.9% of group 2 and 44.5% of group 3, NMO. One of the positive patients in group 1 evolved to NMO. CONCLUSIONS: NMO-IgG determination is crucial in detecting patients who will develop NMO; however, its value as a routine test in cases presenting with symptoms of the type seen in MS is low, and should only be performed in those patients in which the initial diagnosis is not clear.

Change in the clinical activity of multiple sclerosis after treatment switch for suboptimal response.

BACKGROUND: Therapy for multiple sclerosis (MS) has a partial efficacy, and a significant proportion of treated patients will develop a suboptimal response with first-line disease-modifying drugs (DMD). Therapy switch in patients with MS can be a strategy after a treatment failure. We studied the change in clinical activity after switching of first-line DMD because of a treatment failure. METHODS: Relapsing-remitting multiple sclerosis (RRMS) patients treated with interferon-beta (IFNB) or glatiramer acetate (GA) were divided into (i) patients without change in DMD, (ii) patients with a change in DMD because of a poor response, and (iii) those with a change in DMD without relation with response. Annualized relapse rate (ARR) and relapse-free proportions were analyzed. RESULTS: We identified 923 patients with RRMS. Of the 180 who experienced a change because of suboptimal response, 90 switched to another first-line DMT, 38 to mitoxantrone, and 52 to natalizumab. Median ARR in the pre-DMD period on first DMD and second DMD was the following: 1, 1, and 0 for switchers from IFNB to another IFNB (P = 0.0001); 0.67, 1, and 0 for switchers from GA to IFNB (P = 0.01); 1, 1, and 0 for switchers from an IFNB to GA (P = 0.02); 1.1, 1.5, 0.2 for switchers from IFNB or GA to mitoxantrone (P = 0.0001); 0.9, 1, 0 for switchers from IFNB or GA to natalizumab (P = 0.0001). CONCLUSIONS: In patients with RRMS who have a poor response, switch to another DMD may reduce the clinical activity of the disease.

Sertaconazole antifungal profile determined by a microdilution method versus nine topical substances against dermatophyte fungi.

Antifungal activity and in vitro inhibition time for sertaconazole (STZ) and 9 other topical drugs, namely amorolfine, bifonazole, clotrimazole, econazole, ketoconazole, miconazole, oxiconazole, terbinafine, and tioconazole were determined against 124 clinical isolates of dermatophyte (12 species) fungi by the microdilution method in a liquid medium and the measurement of optical density. STZ's antifungal activity was not always affected by the tested dermatophyte genus, as was the case with the remaining antifungals. In vitro antifungal activity was at the same level for all the studied azole derivatives, but, in terms of partial inhibitory concentrations, STZ starts its in vitro inhibitory activity in a shorter time than the other tested substances, particularly in those incubation periods when the growth of the dermatophyte fungi was more developed.

Grey matter damage and overall cognitive impairment in primary progressive multiple sclerosis.

OBJECTIVES: To identify associations between cognitive impairment and imaging measures in a cross-sectional study of patients with primary progressive multiple sclerosis (PPMS). METHODS: Neuropsychological tests were administered to 27 patients with PPMS and 31 controls. Patients underwent brain conventional magnetic resonance imaging (MRI) sequences, volumetric scans and magnetization transfer (MT) imaging; MT ratio (MTR) parameters, grey matter (GM) and normal-appearing white matter (NAWM) volumes, and WM T2 lesion load (T2LL) were obtained. In patients, multiple linear regression models identified the imaging measure associated with the abnormal cognitive tests independently from the other imaging variables. Partial correlation coefficients (PCC) were reported. RESULTS: Patients performed worse on tests of attention/speed of visual information processing, delayed verbal memory, and executive function, and had a worse overall cognitive performance index, when compared with controls. In patients, a lower GM peak location MTR was associated with worse overall cognitive performance (p < 0.001, PCC = 0.77). GM mean and peak height MTR showed the strongest association with the estimated verbal intelligence quotient (IQ) decline (p < 0.001, PCC = -0.62), and executive function (p < 0.001, PCC = 0.79). NAWM volume was associated with attention/speed of visual information processing (p < 0.001, PCC = 0.74), while T2LL was associated with delayed verbal memory (p = 0.007, PCC = -0.55). CONCLUSIONS: The finding of strong associations between GM MTR, NAWM volume and T2LL and specific cognitive impairments suggests that models that predict cognitive impairment in PPMS should include comprehensive MRI assessments of both GM and WM. However, GM MTR appears to be the main correlate of overall cognitive dysfunction, underlining the role of abnormal GM integrity in determining cognitive impairment in PPMS.

An observational study of the effectiveness and safety of natalizumab in the treatment of multiple sclerosis.

AIM: To analyse the safety and effectiveness of natalizumab in the treatment of multiple sclerosis in a real clinical practice setting and according to the approved indications. PATIENTS AND METHODS: All patients with multiple sclerosis treated with natalizumab in our centre were evaluated. The clinical and radiological disease activity during the first year of treatment was analyzed in patients who received at least 12 doses of the drug. The data regarding moderate and severe adverse events in the entire study sample was also evaluated. RESULTS: A total of 112 patients were included in the study, of which 110 had been previously treated with other drugs and 76 had received at least 12 doses of natalizumab. In this group, the annualized relapse rate was reduced by 89% compared to the preceding year and 80% of patients were free from relapses after one year of treatment. Nine percent of patients exhibited 3-month confirmed disability progression. At month 12, the mean number of gadolinium-enhancing lesions on brain MRI was decreased by 99% compared to the pre-treatment MRI. During the first year of treatment, 76% of patients remained free from clinical activity and 33% remained free from both clinical and radiological disease activity. Twenty-nine percent of patients had at least one moderate or severe adverse event, which led to treatment discontinuation in 6%. Four percent of patients experienced immediate hypersensitivity reactions. CONCLUSION: This study suggests that natalizumab is effective in reducing disease activity in patients with relapsing multiple sclerosis and inadequate response to other therapies, with a favorable risk-benefit ratio.

Complementary roles of grey matter MTR and T2 lesions in predicting progression in early PPMS.

OBJECTIVE: To investigate whether T2 lesion load and magnetisation transfer ratio (MTR) in the normal-appearing white matter (NAWM) and grey matter (GM) at study entry are independent predictors of progression and whether their changes correlate with the accrual of disability, over 5 years in early primary progressive multiple sclerosis (PPMS). METHODS: Forty-seven patients with early PPMS and 18 healthy controls were recruited at baseline and invited to attend clinical 6-monthly assessments for 3 years, and after 5 years. Patients were scored on the Expanded Disability Status Scale and multiple sclerosis functional composite subtests (25-foot timed walk test (TWT), nine-hole peg test and paced auditory serial addition test). At each time point, all subjects underwent brain MRI including T2-weighted, magnetisation transfer and volumetric sequences. T2 lesion load (T2LL), MTR histogram parameters and volumes for NAWM and GM were calculated. Statistical analyses identified predictors of progression and correlations between MRI changes and clinical changes over time. RESULTS: Baseline T2LL and GM peak location and peak height MTR were independent predictors of progression, as measured by TWT; a model including these three predictors explained 91% of the variance of the progression on TWT, a significantly higher percentage than that obtained when the predictors were modelled individually (80%, 74% and 68%, respectively). A greater progression rate correlated with a steeper increase in T2LL and a faster decline in GM mean and peak location MTR. CONCLUSIONS: The combined assessment of both visible white matter damage and GM involvement is useful in predicting progression in PPMS.

Antifungal activity of posaconazole against Candida spp. and non-Candida clinical yeasts isolates.

The in vitro antifungal activity of posaconazole was tested against 315 yeast clinical isolates and 11 ATCC reference strains by means an agar diffusion method (Neosensitabs, Rosco,Denmark) based in CLSI M44-A2 document. Posaconazole activity was excellent against Cryptococcus and Rhodotorula species studied and showed very good activity against most species of Candida tested. A total of 13 clinical isolates (4.1%) were resistant: Candida albicans (n=5), Candida glabrata (n=5), Candida tropicalis (n=1), Geotrichum australiensis (n=1) and Geotrichum capitatum (n=1). Our results suggest posaconazole is an effective antifungal agent against the most clinically important yeasts species (92.7% of susceptibility). Agar diffusion method provides good conditions for the posaconazole susceptibility study in the routine laboratory.

34P(7Li,7Be+γ) reaction at 100A MeV in inverse kinematics.

We report on the first successful extraction of a ß+ Gamow-Teller strength distribution from a radioactive isotope in an intermediate-energy charge-exchange experiment in inverse kinematics. The (7Li,7Be+γ(429 keV)) reaction at 100A MeV was used to measure Gamow-Teller transition strengths from 34P to states in 34Si. The results show that little mixing occurs between sd and pf shell configurations for the low-lying 0+ and 2+ states even though 34Si neighbors the island of inversion and low-lying 2ℏω intruder states exist. Shell-model calculations in the sdpf model space are consistent with these findings.

Clinical features of CIS of the brainstem/cerebellum of the kind seen in MS.

Recognition of multiple sclerosis (MS) attacks relies mostly on clinical assessment. However, their definition based on McDonald criteria refers mostly to timing and when dealing with clinical features is rather ambiguous: "...of the kind seen in multiple sclerosis." This is heightened in clinically isolated syndromes of the brainstem/cerebellum (CISB), where clinical manifestations can be manifold. This study aimed to describe the clinical features of patients with CISB to improve clinical recognition of patients with brainstem manifestations at the onset of their MS. To this end, we conducted a retrospective analysis of case notes of consecutively recruited patients with CISB assessed within 3 months of symptoms onset. Seventy-five patients were included. Most common brainstem-specific symptoms were: diplopia (68%), facial sensory symptoms (32%) and gait disturbance (31%). Adjusting for follow-up times, total number of symptoms and presence of other brainstem-specific symptoms, only the presence of facial sensory symptoms was predictive of (a lower risk of) conversion to clinically definite (CD) MS (Odds ratio: 0.086; p = 0.007). Neither the total number of brainstem-specific, non brainstem-specific nor the sum of both predicted conversion to CDMS. Results indicate that diplopia, facial sensory symptoms and gait disturbance occur in more than 30% of patients with CISB. Facial sensory symptoms are less associated with conversion to CDMS.

Do multimodal evoked potentials add information to MRI in clinically isolated syndromes?

The role of multimodal evoked potentials (MMEPs) in establishing multiple sclerosis (MS) diagnosis and prognosis has diminished nowadays. The objective of this article is to evaluate whether MMEPs add information to MRI in identifying patients with higher risk of relapse or development of disability after a clinically isolated syndrome (CIS). Patients who underwent visual, somato-sensory and brainstem auditory evoked potentials (EPs) were identified from a cohort of consecutive CIS. Patients also underwent brain MRI within 3 months of first attack. We analysed time to second attack and to Expanded Disability Status Scale (EDSS) score of 3.0 according to number of Barkhof criteria and number of abnormal MMEPs. A complete study was performed in 245 patients who were followed for a mean of 76.4 months (interquartile range: 61 to 96). Seventy-one patients (29%) had the three EPs normal, 115 patients (47%) had one abnormal EP; 40 patients (16%) had two; and 19 patients (8%) had three abnormal EPs. Baseline MRI determined the risk for converting to clinically definite MS and correlated with disability according to previous studies. EPs individually did not modify the risk of conversion or disability. However, the presence of three abnormal EPs increased the risk of reaching moderate disability (hazard ratio 7.0; 1.4-34.9) independently of baseline MRI. In conclusion, in the presence of three abnormal EPs could help identify CIS patients with a higher risk of developing disability, independently of MRI findings. However, the utility of MMEPs is limited by the low percentage of CIS patients having the three abnormal at baseline.

Primary progressive multiple sclerosis diagnostic criteria: a reappraisal.

The diagnostic criteria used in primary progressive (PP) and relapsing-remitting (RR) multiple sclerosis (MS) show substantial differences. This introduces complexity in the diagnosis of MS which could be resolved if these criteria could be unified in terms of the requirements for dissemination in space (DIS). The aim of this study was to assess whether a single algorithm may be used to demonstrate DIS in all forms of MS. Five sets of RRMS criteria for DIS were applied to a cohort of 145 patients with established PPMS (mean disease duration: 11 years - PPMS-1): C1: Barkhof-Tintoré (as in 2005 McDonald's criteria); C2: Swanton et al. (as in JNNP 2006); C3: presence of oligoclonal bands plus two lesions (as in McDonald's criteria); C4 and C5: a two-step approach was also followed (patients not fulfilling C1 or C2 were then assessed for C3). Two sets of PPMS criteria for DIS were applied: C6: Thompson et al. (as in 2001 McDonald's criteria); C7: 2005 McDonald criteria. A second sample of 55 patients with less than 5 years of disease duration (PPMS-2) was also analysed using an identical approach. For PPMS-1/PPMS-2, fulfilment was: C1:73.8%/66.7%; C2:72.1%/59.3%; C3:89%/79.2%; C4:96%/92.3%; C5:96%/85.7%; C6:85.8%/78.7%; C7:91%/80.4%. Levels of fulfilment suggest that the use of a single set of criteria for DIS in RRMS and PPMS might be feasible, and reinforce the added value of cerebrospinal fluid (CSF) findings to increase fulfilment in PPMS. Unification of the DIS criteria for both RRMS and PPMS could be considered in further revisions of the MS diagnostic criteria.