Characteristics, Prevalence, and Clinical Relevance of Juxtacortical Paramagnetic Rims in Patients With Multiple Sclerosis

BACKGROUND AND OBJECTIVES

A subgroup of patients with multiple sclerosis (MS) presents focal paramagnetic rims at the border between cortex and white matter (juxtacortical paramagnetic rims [JPRs]). We investigated the presence of this finding in our in vivo MS cohort and explored its potential clinical relevance. Moreover, we exploited postmortem MRI of fixed whole MS brains to (1) detect those rims and (2) investigate their histologic correlation.

METHODS

Quantitative susceptibility mapping (QSM) and magnetization-prepared 2 rapid acquisition gradient-echo (MP2RAGE) images at 3T-MRI of 165 patients with MS from the in vivo cohort were screened for JPRs and the presence of cortical lesions. Five postmortem brains from patients with MS were imaged with 3T-MRI to obtain QSM and MP2RAGE sequences. Tissue blocks containing JPRs were excised and paraffin-embedded slices stained by immunohistochemistry for myelin basic protein (for myelin) and anti-CR3/43 (for major histocompatibility complex II-positive microglia/macrophages). DAB-Turnbull stain was performed to detect iron.

RESULTS

JPRs are present in approximately 10% of in vivo patients and are associated with increased cortical lesion load. One of the 5 postmortem brains showed JPRs. Histologically, JPRs correspond to an accumulation of activated iron-laden phagocytes and are associated with demyelination of the whole overlying cortical ribbon.

DISCUSSION

JPRs are a novel potential MRI biomarker of focal cortical demyelination, which seems related to global cortical pathology and might be useful for diagnostic and stratification purposes in a clinical setting.

A Multicenter Longitudinal MRI Study Assessing LeMan-PV Software Accuracy in the Detection of White Matter Lesions in Multiple Sclerosis Patients

BACKGROUND

Detecting new and enlarged lesions in multiple sclerosis (MS) patients is needed to determine their disease activity. LeMan-PV is a software embedded in the scanner reconstruction system of one vendor, which automatically assesses new and enlarged white matter lesions (NELs) in the follow-up of MS patients; however, multicenter validation studies are lacking.

PURPOSE

To assess the accuracy of LeMan-PV for the longitudinal detection NEL white-matter MS lesions in a multicenter clinical setting.

STUDY TYPE

Retrospective, longitudinal.

SUBJECTS

A total of 206 patients with a definitive MS diagnosis and at least two follow-up MRI studies from five centers participating in the Swiss Multiple Sclerosis Cohort study. Mean age at first follow-up = 45.2 years (range: 36.9-52.8 years); 70 males.

FIELD STRENGTH/SEQUENCE

Fluid attenuated inversion recovery (FLAIR) and T1-weighted magnetization prepared rapid gradient echo (T1-MPRAGE) sequences at 1.5 T and 3 T.

ASSESSMENT

The study included 313 MRI pairs of datasets. Data were analyzed with LeMan-PV and compared with a manual "reference standard" provided by a neuroradiologist. A second rater (neurologist) performed the same analysis in a subset of MRI pairs to evaluate the rating-accuracy. The Sensitivity (Se), Specificity (Sp), Accuracy (Acc), F1-score, lesion-wise False-Positive-Rate (aFPR), and other measures were used to assess LeMan-PV performance for the detection of NEL at 1.5 T and 3 T. The performance was also evaluated in the subgroup of 123 MRI pairs at 3 T.

STATISTICAL TESTS

Intraclass correlation coefficient (ICC) and Cohen's kappa (CK) were used to evaluate the agreement between readers.

RESULTS

The interreader agreement was high for detecting new lesions (ICC = 0.97, Pvalue < 10-20 , CK = 0.82, P value = 0) and good (ICC = 0.75, P value < 10-12 , CK = 0.68, P value = 0) for detecting enlarged lesions. Across all centers, scanner field strengths (1.5 T, 3 T), and for NEL, LeMan-PV achieved: Acc = 61%, Se = 65%, Sp = 60%, F1-score = 0.44, aFPR = 1.31. When both follow-ups were acquired at 3 T, LeMan-PV accuracy was higher (Acc = 66%, Se = 66%, Sp = 66%, F1-score = 0.28, aFPR = 3.03).

DATA CONCLUSION

In this multicenter study using clinical data settings acquired at 1.5 T and 3 T, and variations in MRI protocols, LeMan-PV showed similar sensitivity in detecting NEL with respect to other recent 3 T multicentric studies based on neural networks. While LeMan-PV performance is not optimal, its main advantage is that it provides automated clinical decision support integrated into the radiological-routine flow.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 2.

An investigation of the association between focal damage and global network properties in cognitively impaired and cognitively preserved patients with multiple sclerosis

Introduction

The presence of focal cortical and white matter damage in patients with multiple sclerosis (pwMS) might lead to specific alterations in brain networks that are associated with cognitive impairment. We applied microstructure-weighted connectomes to investigate (i) the relationship between global network metrics and information processing speed in pwMS, and (ii) whether the disruption provoked by focal lesions on global network metrics is associated to patients' information processing speed.

Materials and methods

Sixty-eight pwMS and 92 healthy controls (HC) underwent neuropsychological examination and 3T brain MRI including multishell diffusion (dMRI), 3D FLAIR, and MP2RAGE. Whole-brain deterministic tractography and connectometry were performed on dMRI. Connectomes were obtained using the Spherical Mean Technique and were weighted for the intracellular fraction. We identified white matter lesions and cortical lesions on 3D FLAIR and MP2RAGE images, respectively. PwMS were subdivided into cognitively preserved (CPMS) and cognitively impaired (CIMS) using the Symbol Digit Modalities Test (SDMT) z-score at cut-off value of -1.5 standard deviations. Statistical analyses were performed using robust linear models with age, gender, and years of education as covariates, followed by correction for multiple testing.

Results

Out of 68 pwMS, 18 were CIMS and 50 were CPMS. We found significant changes in all global network metrics in pwMS vs HC (p < 0.05), except for modularity. All global network metrics were positively correlated with SDMT, except for modularity which showed an inverse correlation. Cortical, leukocortical, and periventricular lesion volumes significantly influenced the relationship between (i) network density and information processing speed and (ii) modularity and information processing speed in pwMS. Interestingly, this was not the case, when an exploratory analysis was performed in the subgroup of CIMS patients.

Discussion

Our study showed that cortical (especially leukocortical) and periventricular lesions affect the relationship between global network metrics and information processing speed in pwMS. Our data also suggest that in CIMS patients increased focal cortical and periventricular damage does not linearly affect the relationship between network properties and SDMT, suggesting that other mechanisms (e.g. disruption of local networks, loss of compensatory processes) might be responsible for the development of processing speed deficits.

Fluid and White Matter Suppression: New Sensitive 3 T Magnetic Resonance Imaging Contrasts for Cortical Lesion Detection in Multiple Sclerosis

OBJECTIVE

Cortical lesions are common in multiple sclerosis (MS), but their visualization is challenging on conventional magnetic resonance imaging. The uniform image derived from magnetization prepared 2 rapid acquisition gradient echoes (MP2RAGE uni ) detects cortical lesions with a similar rate as the criterion standard sequence, double inversion recovery. Fluid and white matter suppression (FLAWS) provides multiple reconstructed contrasts acquired during a single acquisition. These contrasts include FLAWS minimum image (FLAWS min ), which provides an exquisite sensitivity to the gray matter signal and therefore may facilitate cortical lesion identification, as well as high contrast FLAWS (FLAWS hco ), which gives a contrast that is similar to one of MP2RAGE uni . In this study, we compared the manual detection rate of cortical lesions on MP2RAGE uni , FLAWS min , and FLAWS hco in MS patients. Furthermore, we assessed whether the combined detection rate on FLAWS min and FLAWS hco was superior to MP2RAGE uni for cortical lesions identification. Last, we compared quantitative T1 maps (qT1) provided by both MP2RAGE and FLAWS in MS lesions.

MATERIALS AND METHODS

We included 30 relapsing-remitting MS patients who underwent MP2RAGE and FLAWS magnetic resonance imaging with isotropic spatial resolution of 1 mm at 3 T. Cortical lesions were manually segmented by consensus of 3 trained raters and classified as intracortical or leukocortical lesions on (1) MP2RAGE uniform/flat images, (2) FLAWS min , and (3) FLAWS hco . In addition, segmented lesions on FLAWS min and FLAWS hco were merged to produce a union lesion map (FLAWS min + hco ). Number and volume of all cortical, intracortical, and leukocortical lesions were compared among MP2RAGE uni , FLAWS min , and FLAWS hco using Friedman test and between MP2RAGE uni and FLAWS min + hco using Wilcoxon signed rank test. The FLAWS T1 maps were then compared with the reference MP2RAGE T1 maps using relative differences in percentage. In an exploratory analysis, individual cortical lesion counts of the 3 raters were compared, and interrater variability was quantified using Fleiss ϰ.

RESULTS

In total, 633 segmentations were made on the 3 contrasts, corresponding to 355 cortical lesions. The median number and volume of single cortical, intracortical, and leukocortical lesions were comparable among MP2RAGE uni , FLAWS min , and FLAWS hco . In patients with cortical lesions (22/30), median cumulative lesion volume was larger on FLAWS min (587 μL; IQR, 1405 μL) than on MP2RAGE uni (490 μL; IQR, 990 μL; P = 0.04), whereas there was no difference between FLAWS min and FLAWS hco , or FLAWS hco and MP2RAGE uni . FLAWS min + hco showed significantly greater numbers of cortical (median, 4.5; IQR, 15) and leukocortical (median, 3.5; IQR, 12) lesions than MP2RAGE uni (median, 3; IQR, 10; median, 2.5; IQR, 7; both P < 0.001). Interrater agreement was moderate on MP2RAGE uni (ϰ = 0.582) and FLAWS hco (ϰ = 0.584), but substantial on FLAWS min (ϰ = 0.614). qT1 in lesions was similar between MP2RAGE and FLAWS.

CONCLUSIONS

Cortical lesions identification in FLAWS min and FLAWS hco was comparable to MP2RAGE uni . The combination of FLAWS min and FLAWS hco allowed to identify a higher number of cortical lesions than MP2RAGE uni , whereas qT1 maps did not differ between the 2 acquisition schemes.

A comparative assessment of myelin-sensitive measures in multiple sclerosis patients and healthy subjects

INTRODUCTION

Multiple Sclerosis (MS) is a common neurological disease primarily characterized by myelin damage in lesions and in normal - appearing white and gray matter (NAWM, NAGM). Several quantitative MRI (qMRI) methods are sensitive to myelin characteristics by measuring specific tissue biophysical properties. However, there are currently few studies assessing the relative reproducibility and sensitivity of qMRI measures to MS pathology in vivo in patients.

METHODS

We performed two studies. The first study assessed of the sensitivity of qMRI measures to MS pathology: in this work, we recruited 150 MS and 100 healthy subjects, who underwent brain MRI at 3 T including quantitative T1 mapping (qT1), quantitative susceptibility mapping (QSM), magnetization transfer saturation imaging (MTsat) and myelin water imaging for myelin water fraction (MWF). The sensitivity of qMRIs to MS focal pathology (MS lesions vs peri-plaque white/gray matter (PPWM/PPGM)) was studied lesion-wise; the sensitivity to diffuse normal appearing (NA) pathology was measured using voxel-wise threshold-free cluster enhancement (TFCE) in NAWM and vertex-wise inflated cortex analysis in NAGM. Furthermore, the sensitivity of qMRI to the identification of lesion tissue was investigated using a voxel-wise logistic regression analysis to distinguish MS lesion and PP voxels. The second study assessed the reproducibility of myelin-sensitive qMRI measures in a single scanner. To evaluate the intra-session and inter-session reproducibility of qMRI measures, we have investigated 10 healthy subjects, who underwent two brain 3 T MRIs within the same day (without repositioning), and one after 1-week interval. Five region of interest (ROIs) in white and deep grey matter areas were segmented, and inter- and intra- session reproducibility was studied using the intra-class correlation coefficient (ICC). Further, we also investigated the voxel-wise reproducibility of qMRI measures in NAWM and NAGM.

RESULTS

qT1 and QSM showed the highest sensitivity to distinguish MS focal WM and cortical pathology from peri-plaque WM (P < 0.0001), although QSM also showed the highest variance when applied to lesions. MWF and MTsat exhibited the highest sensitivity to NAWM pathology (P < 0.01). On the other hand, qT1 appeared to be the most sensitive measure to NAGM pathology (P < 0.01). All myelin-sensitive qMRI measures exhibited high inter/intra sessional ICCs in various WM and deep GM ROIs, in NAWM and in NAGM (ICC 0.82 ± 0.12).

CONCLUSION

This work shows that the applied qT1, MWF, MTsat and QSM are highly reproducible and exhibit differential sensitivity to focal and diffuse WM and GM pathology in MS patients.

A new advanced MRI biomarker for remyelinated lesions in Multiple Sclerosis

Objectives

Neuropathological studies have shown that multiple sclerosis (MS) lesions are heterogeneous in terms of myelin/axon damage and repair as well as iron content. However, it remains a challenge to identify specific chronic lesion types, especially remyelinated lesions, in vivo in patients with MS.

Methods

We performed 3 studies: (1) a cross‐sectional study in a prospective cohort of 115 patients with MS and 76 healthy controls, who underwent 3 T magnetic resonance imaging (MRI) for quantitative susceptibility mapping (QSM), myelin water fraction (MWF), and neurite density index (NDI) maps. White matter (WM) lesions in QSM were classified into 5 QSM lesion types (iso‐intense, hypo‐intense, hyperintense, lesions with hypo‐intense rims, and lesions with paramagnetic rim legions [PRLs]); (2) a longitudinal study of 40 patients with MS to study the evolution of lesions over 2 years; (3) a postmortem histopathology‐QSM validation study in 3 brains of patients with MS to assess the accuracy of QSM classification to identify neuropathological lesion types in 63 WM lesions.

Results

At baseline, hypo‐ and isointense lesions showed higher mean MWF and NDI values compared to other QSM lesion types (p < 0.0001). Further, at 2‐year follow‐up, hypo‐/iso‐intense lesions showed an increase in MWF. Postmortem analyses revealed that QSM highly accurately identifies (1) fully remyelinated areas as hypo‐/iso‐intense (sensitivity = 88.89% and specificity = 100%), (2) chronic inactive lesions as hyperintense (sensitivity = 71.43% and specificity = 92.00%), and (3) chronic active/smoldering lesions as PRLs (sensitivity = 92.86% and specificity = 86.36%).

Interpretation

These results provide the first evidence that it is possible to distinguish chronic MS lesions in a clinical setting, hereby supporting with new biomarkers to develop and assess remyelinating treatments. ANN NEUROL 2022;92:486–502

Association of Brain Atrophy With Disease Progression Independent of Relapse Activity in Patients With Relapsing Multiple Sclerosis

Importance

The mechanisms driving neurodegeneration and brain atrophy in relapsing multiple sclerosis (RMS) are not completely understood.

Objective

To determine whether disability progression independent of relapse activity (PIRA) in patients with RMS is associated with accelerated brain tissue loss.

Design, Setting, and Participants

In this observational, longitudinal cohort study with median (IQR) follow-up of 3.2 years (2.0-4.9), data were acquired from January 2012 to September 2019 in a consortium of tertiary university and nonuniversity referral hospitals. Patients were included if they had regular clinical follow-up and at least 2 brain magnetic resonance imaging (MRI) scans suitable for volumetric analysis. Data were analyzed between January 2020 and March 2021.

Exposures

According to the clinical evolution during the entire observation, patients were classified as those presenting (1) relapse activity only, (2) PIRA episodes only, (3) mixed activity, or (4) clinical stability.

Main Outcomes and Measures

Mean difference in annual percentage change (MD-APC) in brain volume/cortical thickness between groups, calculated after propensity score matching. Brain atrophy rates, and their association with the variables of interest, were explored with linear mixed-effect models.

Results

Included were 1904 brain MRI scans from 516 patients with RMS (67.4% female; mean [SD] age, 41.4 [11.1] years; median [IQR] Expanded Disability Status Scale score, 2.0 [1.5-3.0]). Scans with insufficient quality were excluded (n = 19). Radiological inflammatory activity was associated with increased atrophy rates in several brain compartments, while an increased annualized relapse rate was linked to accelerated deep gray matter (GM) volume loss. When compared with clinically stable patients, patients with PIRA had an increased rate of brain volume loss (MD-APC, -0.36; 95% CI, -0.60 to -0.12; P = .02), mainly driven by GM loss in the cerebral cortex. Patients who were relapsing presented increased whole brain atrophy (MD-APC, -0.18; 95% CI, -0.34 to -0.02; P = .04) with respect to clinically stable patients, with accelerated GM loss in both cerebral cortex and deep GM. No differences in brain atrophy rates were measured between patients with PIRA and those presenting relapse activity.

Conclusions and Relevance

Our study shows that patients with RMS and PIRA exhibit accelerated brain atrophy, especially in the cerebral cortex. These results point to the need to recognize the insidious manifestations of PIRA in clinical practice and to further evaluate treatment strategies for patients with PIRA in clinical trials.

Chronic White Matter Inflammation and Serum Neurofilament Levels in Multiple Sclerosis

OBJECTIVE

To assess whether chronic white matter inflammation in patients with multiple sclerosis (MS) as detected in vivo by paramagnetic rim MRI lesions (PRLs) is associated with higher serum neurofilament light chain (sNfL) levels, a marker of neuroaxonal damage.

METHODS

In 118 patients with MS with no gadolinium-enhancing lesions or recent relapses, we analyzed 3D-submillimeter phase MRI and sNfL levels. Histopathologic evaluation was performed in 25 MS lesions from 20 additional autopsy MS cases.

RESULTS

In univariable analyses, participants with ≥2 PRLs (n = 43) compared to those with ≤1 PRL (n = 75) had higher age-adjusted sNfL percentiles (median, 91 and 68; p < 0.001) and higher Multiple Sclerosis Severity Scale scores (MSSS median, 4.3 and 2.4; p = 0.003). In multivariable analyses, sNfL percentile levels were higher in PRLs ≥2 cases (β_add, 16.3; 95% confidence interval [CI], 4.6-28.0; p < 0.01), whereas disease-modifying treatment (DMT), Expanded Disability Status Scale (EDSS) score, and T2 lesion load did not affect sNfL. In a similar model, sNfL percentile levels were highest in cases with ≥4 PRLs (n = 30; β_add, 30.4; 95% CI, 15.6-45.2; p < 0.01). Subsequent multivariable analysis revealed that PRLs ≥2 cases also had higher MSSS (β_add, 1.1; 95% CI, 0.3-1.9; p < 0.01), whereas MSSS was not affected by DMT or T2 lesion load. On histopathology, both chronic active and smoldering lesions exhibited more severe acute axonal damage at the lesion edge than in the lesion center (edge vs center: p = 0.004 and p = 0.0002, respectively).

CONCLUSION

Chronic white matter inflammation was associated with increased levels of sNfL and disease severity in nonacute MS, suggesting that PRL contribute to clinically relevant, inflammation-driven neurodegeneration.

Intrathecal Immunoglobulin M Synthesis is an Independent Biomarker for Higher Disease Activity and Severity in Multiple Sclerosis

OBJECTIVE

We aimed to determine in relapsing multiple sclerosis (MS) whether intrathecal synthesis of immunoglobulin (Ig) M and IgG is associated with outcomes reflecting inflammatory activity and chronic worsening.

METHODS

We compared cerebrospinal fluid analysis, clinical and magnetic resonance imaging data, and serum neurofilament light chain (sNfL) levels at baseline and follow-up in 530 patients with relapsing MS. Patients were categorized by the presence of oligoclonal IgG bands (OCGB) and intrathecal synthesis of IgG and IgM (intrathecal fraction [IF]: IgG_IF and IgM_IF ). Relationships with the time to first relapse, sNfL concentrations, T2-weighted (T2w) lesions, MS Severity Score (MSSS), and time to initiation of high-efficacy therapy were analyzed in covariate-adjusted statistical models.

RESULTS

By categorical analysis, in patients with IgM_IF the median time to first relapse was 28 months shorter and MSSS on average higher by 1.11 steps compared with patients without intrathecal immunoglobulin synthesis. Moreover, patients with IgM_IF had higher sNfL concentrations, more new/enlarging T2w lesions, and higher total T2w lesion counts (all p ≤ 0.01). These associations were absent or equally smaller in patients who were positive for only OCGB or OCGB/IgG_IF . Furthermore, quantitative analyses revealed that in patients with IgM_IF  ≥ median, the time to first relapse and to initiation of high-efficacy therapy was shorter by 32 and by 203 months, respectively (both p < 0.01), in comparison to patients with IgM_IF  < median. Dose-dependent associations were also found for IgM_IF but not for IgG_IF with magnetic resonance imaging-defined disease activity and sNfL.

INTERPRETATION

This large study supports the value of intrathecal IgM synthesis as an independent biomarker of disease activity and severity in relapsing MS. ANN NEUROL 2021.

GAMER-MRI in Multiple Sclerosis Identifies the Diffusion-Based Microstructural Measures That Are Most Sensitive to Focal Damage: A Deep-Learning-Based Analysis and Clinico-Biological Validation

Conventional magnetic resonance imaging (cMRI) in multiple sclerosis (MS) patients provides measures of focal brain damage and activity, which are fundamental for disease diagnosis, prognosis, and the evaluation of response to therapy. However, cMRI is insensitive to the damage to the microenvironment of the brain tissue and the heterogeneity of MS lesions. In contrast, the damaged tissue can be characterized by mathematical models on multishell diffusion imaging data, which measure different compartmental water diffusion. In this work, we obtained 12 diffusion measures from eight diffusion models, and we applied a deep-learning attention-based convolutional neural network (CNN) (GAMER-MRI) to select the most discriminating measures in the classification of MS lesions and the perilesional tissue by attention weights. Furthermore, we provided clinical and biological validation of the chosen metrics-and of their most discriminative combinations-by correlating their respective mean values in MS patients with the corresponding Expanded Disability Status Scale (EDSS) and the serum level of neurofilament light chain (sNfL), which are measures of disability and neuroaxonal damage. Our results show that the neurite density index from neurite orientation and dispersion density imaging (NODDI), the measures of the intra-axonal and isotropic compartments from microstructural Bayesian approach, and the measure of the intra-axonal compartment from the spherical mean technique NODDI were the most discriminating (respective attention weights were 0.12, 0.12, 0.15, and 0.13). In addition, the combination of the neurite density index from NODDI and the measures for the intra-axonal and isotropic compartments from the microstructural Bayesian approach exhibited a stronger correlation with EDSS and sNfL than the individual measures. This work demonstrates that the proposed method might be useful to select the microstructural measures that are most discriminative of focal tissue damage and that may also be combined to a unique contrast to achieve stronger correlations to clinical disability and neuroaxonal damage.

Myelin and axon pathology in multiple sclerosis assessed by myelin water and multi-shell diffusion imaging

Damage to the myelin sheath and the neuroaxonal unit is a cardinal feature of multiple sclerosis; however, a detailed characterization of the interaction between myelin and axon damage in vivo remains challenging. We applied myelin water and multi-shell diffusion imaging to quantify the relative damage to myelin and axons (i) among different lesion types; (ii) in normal-appearing tissue; and (iii) across multiple sclerosis clinical subtypes and healthy controls. We also assessed the relation of focal myelin/axon damage with disability and serum neurofilament light chain as a global biological measure of neuroaxonal damage. Ninety-one multiple sclerosis patients (62 relapsing-remitting, 29 progressive) and 72 healthy controls were enrolled in the study. Differences in myelin water fraction and neurite density index were substantial when lesions were compared to healthy control subjects and normal-appearing multiple sclerosis tissue: both white matter and cortical lesions exhibited a decreased myelin water fraction and neurite density index compared with healthy (P < 0.0001) and peri-plaque white matter (P < 0.0001). Periventricular lesions showed decreased myelin water fraction and neurite density index compared with lesions in the juxtacortical region (P < 0.0001 and P < 0.05). Similarly, lesions with paramagnetic rims showed decreased myelin water fraction and neurite density index relative to lesions without a rim (P < 0.0001). Also, in 75% of white matter lesions, the reduction in neurite density index was higher than the reduction in the myelin water fraction. Besides, normal-appearing white and grey matter revealed diffuse reduction of myelin water fraction and neurite density index in multiple sclerosis compared to healthy controls (P < 0.01). Further, a more extensive reduction in myelin water fraction and neurite density index in normal-appearing cortex was observed in progressive versus relapsing-remitting participants. Neurite density index in white matter lesions correlated with disability in patients with clinical deficits (P < 0.01, beta = -10.00); and neurite density index and myelin water fraction in white matter lesions were associated to serum neurofilament light chain in the entire patient cohort (P < 0.01, beta = -3.60 and P < 0.01, beta = 0.13, respectively). These findings suggest that (i) myelin and axon pathology in multiple sclerosis is extensive in both lesions and normal-appearing tissue; (ii) particular types of lesions exhibit more damage to myelin and axons than others; (iii) progressive patients differ from relapsing-remitting patients because of more extensive axon/myelin damage in the cortex; and (iv) myelin and axon pathology in lesions is related to disability in patients with clinical deficits and global measures of neuroaxonal damage.

GAMER MRI: Gated-attention mechanism ranking of multi-contrast MRI in brain pathology

INTRODUCTION

During the last decade, a multitude of novel quantitative and semiquantitative MRI techniques have provided new information about the pathophysiology of neurological diseases. Yet, selection of the most relevant contrasts for a given pathology remains challenging. In this work, we developed and validated a method, Gated-Attention MEchanism Ranking of multi-contrast MRI in brain pathology (GAMER MRI), to rank the relative importance of MR measures in the classification of well understood ischemic stroke lesions. Subsequently, we applied this method to the classification of multiple sclerosis (MS) lesions, where the relative importance of MR measures is less understood.

METHODS

GAMER MRI was developed based on the gated attention mechanism, which computes attention weights (AWs) as proxies of importance of hidden features in the classification. In the first two experiments, we used Trace-weighted (Trace), apparent diffusion coefficient (ADC), Fluid-Attenuated Inversion Recovery (FLAIR), and T1-weighted (T1w) images acquired in 904 acute/subacute ischemic stroke patients and in 6,230 healthy controls and patients with other brain pathologies to assess if GAMER MRI could produce clinically meaningful importance orders in two different classification scenarios. In the first experiment, GAMER MRI with a pretrained convolutional neural network (CNN) was used in conjunction with Trace, ADC, and FLAIR to distinguish patients with ischemic stroke from those with other pathologies and healthy controls. In the second experiment, GAMER MRI with a patch-based CNN used Trace, ADC and T1w to differentiate acute ischemic stroke lesions from healthy tissue. The last experiment explored the performance of patch-based CNN with GAMER MRI in ranking the importance of quantitative MRI measures to distinguish two groups of lesions with different pathological characteristics and unknown quantitative MR features. Specifically, GAMER MRI was applied to assess the relative importance of the myelin water fraction (MWF), quantitative susceptibility mapping (QSM), T1 relaxometry map (qT1), and neurite density index (NDI) in distinguishing 750 juxtacortical lesions from 242 periventricular lesions in 47 MS patients. Pair-wise permutation t-tests were used to evaluate the differences between the AWs obtained for each quantitative measure.

RESULTS

In the first experiment, we achieved a mean test AUC of 0.881 and the obtained AWs of FLAIR and the sum of AWs of Trace and ADC were 0.11 and 0.89, respectively, as expected based on previous knowledge. In the second experiment, we achieved a mean test F1 score of 0.895 and a mean AW of Trace = 0.49, of ADC = 0.28, and of T1w = 0.23, thereby confirming the findings of the first experiment. In the third experiment, MS lesion classification achieved test balanced accuracy = 0.777, sensitivity = 0.739, and specificity = 0.814. The mean AWs of T1map, MWF, NDI, and QSM were 0.29, 0.26, 0.24, and 0.22 (p < 0.001), respectively.

CONCLUSIONS

This work demonstrates that the proposed GAMER MRI might be a useful method to assess the relative importance of MRI measures in neurological diseases with focal pathology. Moreover, the obtained AWs may in fact help to choose the best combination of MR contrasts for a specific classification problem.

Iran's Approach to COVID-19: Evolving Treatment Protocols and Ongoing Clinical Trials

The coronavirus disease 2019 (COVID-19) pandemic is challenging the health care systems around the world and compelling them to timely share their strategies, tactics and experiences. Since mid-January, a huge volume of instructions has been released by Iran's Ministry of Health and Medical Education (MOHME) covering diverse aspects of disease control and prevention. In this study, we aimed to review the instructions published either before or after COVID-19's transmission to Iran to depict the clinical approach and therapeutics used in Iran to battle the current pandemic. We retrospectively gathered and critically reviewed all official situation reports, guidelines, guidance, flowcharts, protocols, recommendations and advice released by Iranian scientific, or administrative arms of action against COVID-19. The ongoing clinical trials approved by MOHME and registered to the Iranian Registry of Clinical Trials (IRCT) have been reviewed as well. Our study resulted in the following mainstays of Iran's approach to COVID-19: (i) active clinical screening; preferably on-line or on-phone, (ii) management of limited paraclinical resources; by using them as diagnostic tools rather than epidemiological, (iii) a trend toward outpatient care of mild-to-moderate cases; either confirmed or suspicious, with active scheduled follow-up, and (iv) avoidance of pharmacotherapy, as far as possible. The therapeutic and administrative instructions are still being actively updated with some recommendations different from the previous ones. Nevertheless, a common approach in the background could be detected, It seems that the instructions are conceptually in line with the first “National Guideline for 2019-nCoV” published on 20 January 2020. The screening has mainly been clinically oriented rather than being based on laboratory tests and MOHME seems to be following the approach of “early detection of symptomatic cases followed by early source control.”

RimNet: A deep 3D multimodal MRI architecture for paramagnetic rim lesion assessment in multiple sclerosis

OBJECTIVES

In multiple sclerosis (MS), the presence of a paramagnetic rim at the edge of non-gadolinium-enhancing lesions indicates perilesional chronic inflammation. Patients featuring a higher paramagnetic rim lesion burden tend to have more aggressive disease. The objective of this study was to develop and evaluate a convolutional neural network (CNN) architecture (RimNet) for automated detection of paramagnetic rim lesions in MS employing multiple magnetic resonance (MR) imaging contrasts.

MATERIALS AND METHODS

Imaging data were acquired at 3 Tesla on three different scanners from two different centers, totaling 124 MS patients, and studied retrospectively. Paramagnetic rim lesion detection was independently assessed by two expert raters on T2*-phase images, yielding 462 rim-positive (rim+) and 4857 rim-negative (rim-) lesions. RimNet was designed using 3D patches centered on candidate lesions in 3D-EPI phase and 3D FLAIR as input to two network branches. The interconnection of branches at both the first network blocks and the last fully connected layers favors the extraction of low and high-level multimodal features, respectively. RimNet's performance was quantitatively evaluated against experts' evaluation from both lesion-wise and patient-wise perspectives. For the latter, patients were categorized based on a clinically relevant threshold of 4 rim+ lesions per patient. The individual prediction capabilities of the images were also explored and compared (DeLong test) by testing a CNN trained with one image as input (unimodal).

RESULTS

The unimodal exploration showed the superior performance of 3D-EPI phase and 3D-EPI magnitude images in the rim+/- classification task (AUC = 0.913 and 0.901), compared to the 3D FLAIR (AUC = 0.855, Ps < 0.0001). The proposed multimodal RimNet prototype clearly outperformed the best unimodal approach (AUC = 0.943, P < 0.0001). The sensitivity and specificity achieved by RimNet (70.6% and 94.9%, respectively) are comparable to those of experts at the lesion level. In the patient-wise analysis, RimNet performed with an accuracy of 89.5% and a Dice coefficient (or F1 score) of 83.5%.

CONCLUSIONS

The proposed prototype showed promising performance, supporting the usage of RimNet for speeding up and standardizing the paramagnetic rim lesions analysis in MS.

Multiple sclerosis cortical and WM lesion segmentation at 3T MRI: a deep learning method based on FLAIR and MP2RAGE

The presence of cortical lesions in multiple sclerosis patients has emerged as an important biomarker of the disease. They appear in the earliest stages of the illness and have been shown to correlate with the severity of clinical symptoms. However, cortical lesions are hardly visible in conventional magnetic resonance imaging (MRI) at 3T, and thus their automated detection has been so far little explored. In this study, we propose a fully-convolutional deep learning approach, based on the 3D U-Net, for the automated segmentation of cortical and white matter lesions at 3T. For this purpose, we consider a clinically plausible MRI setting consisting of two MRI contrasts only: one conventional T2-weighted sequence (FLAIR), and one specialized T1-weighted sequence (MP2RAGE). We include 90 patients from two different centers with a total of 728 and 3856 gray and white matter lesions, respectively. We show that two reference methods developed for white matter lesion segmentation are inadequate to detect small cortical lesions, whereas our proposed framework is able to achieve a detection rate of 76% for both cortical and white matter lesions with a false positive rate of 29% in comparison to manual segmentation. Further results suggest that our framework generalizes well for both types of lesion in subjects acquired in two hospitals with different scanners.

Respiratory Distress in Postanesthesia Care Unit: First Presentation of Coronavirus Disease 2019 in a 17-Year-Old Girl: A Case Report

A 17-year-old healthy girl underwent an uneventful esthetic septorhinoplasty. She was easily extubated and transferred to the postanesthesia care unit (PACU) with oxygen saturation (SpO2) of 96%. About 30 minutes after arrival in the PACU, she developed dyspnea with SpO2 of 84% and promptly received oxygen with bilevel positive airway pressure in conjunction with low-dose corticosteroid. The subsequent chest computed tomography (CT) revealed bilateral patchy infiltrates similar to the radiologic findings of Coronavirus Disease 2019 (COVID-19). Finally, a reverse transcriptase polymerase chain reaction (RT-PCR) of a pharyngeal specimen confirmed the diagnosis of COVID-19.

The role of opening CSF pressure in response to treatment for idiopathic intracranial hypertension (IIH)

The aim of the current study was to assess the risk factors, clinical symptoms and Cerebrospinal fluid (CSF) pressure of idiopathic intracranial hypertension (IIH) with emphasis on determining the risk factors which involved in poor response to treatment. We retrospectively included 202 patients who were diagnosed with IIH. Disease severity was classified according to prescribed therapeutic option into 4 groups: acetazolamide (group 1), Acetazolamide plus topiramate or Lasix (group 2), repeated LP (group 3) and surgical intervention (group 4). Being in the higher group was considered as a higher severity of disease and poor response to treatment. Among the evaluated features of IIH, the strongest association were observed between opening CSF pressure and disease severity. So that, the highest CSF pressure was observed in patients who underwent surgery, which represent the highest severity of disease (group 4) and poor response to therapy (mean ± SD: 43.9 ± 21.1 cm H₂O). Headache was the most prevalent symptom of IIH in our series which was significantly higher among acetazolamide group. Blurred vision was the second most common symptoms which, unlike the headache was more reported in surgery group. Our results suggested that higher CSF pressure could be the risk factors of poor response to therapy, which may raise need for more intensive treatment. Furthermore, suffering of headache without blurred vision can consider as a prognostic factor for mild severity and good response to treatment.

Multiple sclerosis pathogenesis: missing pieces of an old puzzle

Traditionally, multiple sclerosis (MS) was considered to be a CD4 T cell-mediated CNS autoimmunity, compatible with experimental autoimmune encephalitis model, which can be characterized by focal lesions in the white matter. However, studies of recent decades revealed several missing pieces of MS puzzle and showed that MS pathogenesis is more complex than the traditional view and may include the following: a primary degenerative process (e.g. oligodendroglial pathology), generalized abnormality of normal-appearing brain tissue, pronounced gray matter pathology, involvement of innate immunity, and CD8 T cells and B cells. Here, we review these findings and discuss their implications in MS pathogenesis.

Effect of Co-administration of Bumetanide and Phenobarbital on Seizure Attacks in Temporal Lobe Epilepsy

Introduction:

The resistance of temporal lobe epilepsy to classic drugs is thought to be due to disruption in the excitation/inhibition of this pathway. Two chloride transporters, NKCC1 and KCC2, are expressed differently for the excitatory state of Gamma-Amino Butyric Acid (GABA). The present study explored the effect of bumetanide as a selective NKCC1 inhibitor either alone or in combination with the phenobarbital in the pilocarpine model of epilepsy.

Methods:

An animal model of Status Epilepticus (SE) was induced with pilocarpine in Wistar male rats followed by phenobarbital and or bumetanide or saline administration for 45 days after the induction of SE by Intraperitoneal (IP) injection. The rats were monitored, their behavior was recorded, and after 24 hours they were sacrificed to study the expression of NKCC1 and KCC2 using real time PCR.

Results:

The data showed that the effects of a combination of bumetanide with phenobarbital on frequency rate and duration of seizure attack were more than those of the phenobarbital alone. In addition, in the bumetanide and combined treatment groups, NKCC1 expression decreased significantly, compared with untreated epileptic animals. A delayed decrement in NKCC1/KCC2 expression ratio after bumetanide application was also observed.

Conclusion:

The combination of bumetanide with phenobarbital increases the inhibition of SE and maximizes the potential of GABA signaling pathway, and can be considered as an effective therapeutic strategy in patients with epilepsy.

Prevalence of new-onset migraine in patients with idiopathic intracranial hypertension in comparison to the general population

Background: Idiopathic intracranial hypertension (IIH) encompasses patients with elevated intracranial pressure (ICP). Generally, it is difficult to make a differential diagnosis between IIH and co-existing migraine headaches. Thus, this article intends to estimate the prevalence of migraine in patients with IIH and explain the occurrence of new-onset migraine after the diagnosis of IIH. Methods: The case group included 108 patients with IIH referred to the neurology wards of three university hospitals. A random sample of controls (n = 103) were recruited from patients hospitalized in the surgery and orthopedics ward. A checklist for migraine diagnosis was filled out. Cerebrospinal fluid (CSF) pressure and presence or absence of papilloedema (PE) in the patients and any necessary data were also recorded from the inpatient medical documents. All statistical analyses were done by SPSS software. Results: There were 70 (64.80%) and 22 (21.40%) migraineurs in the case and control groups, respectively, and the difference was found to be significant (P < 0.001). In 26 (37.14%) migraine cases in the IIH group, the disorder was diagnosed after developing IIH. Also, there was a past medical history of having migraine in 44 (62.85%) migraineurs. In the fully adjusted regression models, the odds of being affected by migraine in patients with IIH was 6.17 times greater than the controls [odds ratio (OR) = 7.15, 95% confidence interval (CI) = 3.56-14.36, P < 0.010]. The patients' mean CSF opening pressure was 32.10 ± 1.03 cmH₂O and 93 (81.60%) subjects were found to have PE. Conclusion: It was demonstrated that subjects with IIH might have about a 6-time higher likelihood of developing migraine headache than the general population. These considerations can help prevent misdiagnosis of migraine headache as the recurrence of IIH or uncontrolled IIH and subsequent inappropriate management.

B cells in multiple sclerosis therapy-A comprehensive review

For decades, B cells were ignored in multiple sclerosis (MS) pathogenesis, and the disease was always regarded as a T cell-mediated disorder. Recent evidence shows that there is an antigen-driven B-cell response in the central nervous system of patients with MS, and memory B cells/plasma cells are detectable in MS lesions. The striking efficacy of B cell-depleting therapies in reducing the inflammatory activity of the disease highlights that B cells may play more pathogenetic roles than expected. B cells express several unique characteristic markers on their surface, for example, CD19, CD20 molecules, that provide selective targets for monoclonal antibodies. In this respect, several B cell-targeted therapies emerged, including anti-CD20 antibodies (rituximab, ocrelizumab, and ofatumumab), anti-CD19 antibody (inebilizumab), and agents targeting the BAFF/APRIL signaling pathway (atacicept, belimumab, and LY2127399). In this review, we discuss, in detail, the immunobiology of B cells and their protective and destructive roles in MS pathogenesis. In the second part, we list the completed and ongoing clinical trials investigating the safety and efficacy of B cell-related monoclonal antibodies in MS.

Demyelination with preferential MAG loss: A complex message from MS paraffin blocks

Multiple sclerosis (MS) is generally considered to be a demyelinating autoimmune disorder. However, neuropathological examinations of MS lesions do not support this concept. Demyelination with preferential loss of myelin-associated glycoprotein (MAG) is a common finding in MS tissues and has been reported by several groups. As MAG is located in ad-axonal myelin layers and is not accessible to infiltrating immune cells, demyelination with preferred loss of MAG may be suggestive of a primary oligodendrocytopathy in MS. Moreover, it has been shown that oligodendrocytopathy may precede the infiltration of inflammatory cells at the lesion site. In this paper, we review studies of neuropathology of MS tissues that reported this type of demyelination and then we discuss three emerging explanations that are trying to interpret this mismatched observation.

Pilocytic Astrocytoma of Fornix Mimicking a Colloid Cyst: Report of 2 Cases and Review of the Literature

BACKGROUND

Colloid cyst is a gelatin-containing cyst in the brain almost always found in the third ventricle. The specific shape and location of these cysts, a round well-delineated mass in the rostral part of the third ventricle adjacent to the foramen of Monro, on imaging are the main findings for diagnosis. Several masses of the third ventricle masquerading colloid cysts on images have been reported. Based on different surgical approaches, preoperative misdiagnosis of colloid cyst may have great impact on prognosis.

METHODS

We report 2 cases that presented with severe headache and hydrocephalus, and their preoperative images were highly indicative of colloid cyst.

RESULTS

Histopathologic investigations after tumor resection showed pilocytic astrocytoma of fornix in both cases.

CONCLUSIONS

Fifteen cases of colloid cyst misdiagnosis with other masses have been reported thus far; among them, 2 cases were pilocytic astrocytoma. In this study we report 2 other cases. Furthermore, we discuss additional clues helping to differentiate pilocytic astrocytoma from colloid cyst on images.

Posterior reversible encephalopathy syndrome in a patient with mixed connective tissue disease: a case report

Background

Posterior reversible encephalopathy is a syndrome highly associated with hypertension and cytotoxic therapy. The syndrome typically presents with headache, visual abnormality, seizures and characteristic vasogenic edema on magnetic resonance imaging. The entity warrants a prompt diagnosis to avoid deteriorating consequences.

Case presentation

In this report, we describe a 15-year-old Iranian boy who was diagnosed with mixed connective tissue disease, and cyclophosphamide pulse therapy was administered. Three days after the second pulse of cyclophosphamide, when he was receiving prednisolone and hydroxycholoroquine, our patient developed generalized tonic-clonic seizures. Magnetic resonance imaging findings showed high signal intensities in the posterior areas of his brain. After 8 days, the brain magnetic resonance imaging abnormalities were resolved following the control of his blood pressure and antiepileptic treatment. These observations have been indicative of posterior reversible encephalopathy syndrome. Nevertheless, our patient developed uncontrollable respiratory distress and eventually died.

Conclusions

To the best of our knowledge, this case is the first report of posterior reversible encephalopathy syndrome in a patient with mixed connective tissue disease. As the patient developed posterior reversible encephalopathy syndrome 3 days after cyclophosphamide pulse therapy to reduce the disease activity, it is hard to accurately determine whether posterior reversible encephalopathy syndrome in this case is a complication of cyclophosphamide or a condition that resulted from the mixed connective tissue disease flare-up.

BDNF modifies hippocampal KCC2 and NKCC1 expression in a temporal lobe epilepsy model

Excitatory GABA actions, induced by altered expression of chloride transporters (KCC2/NKCC1), can contribute to seizure generation in temporal lobe epilepsy. In the present study, we evaluated whether BDNF administration can affect KCC2/NKCC1 expression, ictogenesis and behavioral alterations in this paradigm. Status epilepticus was induced in male rats with pilocarpine, followed by a treatment of either a single high dose or multiple injections of BDNF during the latent phase of temporal lobe epilepsy. Chloride transporters expression, spontaneous recurrent seizures, and hyperexcitability post-seizural behaviors were evaluated after treatment. NKCC1 protein expression was markedly upregulated, whereas that of KCC2 was significantly downregulated in epileptic hippocampi compared to intact controls. Application of BDNF (both single high dose and multiple injections) increased KCC2 expression in epileptic hippocampi, while NKCC1 expression was downregulated exclusively by the single high dose injection of BDNF. Development of spontaneous recurrent seizures was delayed but not prevented by the treatment, and hyperexcitability behaviors were ameliorated for a short period of time. To prevent GABA-A mediated depolarization and design appropriate treatment strategies for temporal lobe epilepsy, chloride transporters can be considered as a target. Future studies are warranted to investigate any possible therapeutic effects of BDNF via altering chloride transporters expression.

Laser-based gene transfection and gene therapy

The plasma membrane of mammalian cells can be transiently permeablized by optical means and exogenous materials or genes can be introduced into the cytoplasm of living cells. Until now, few mechanisms were exploited for the manipulation: laser is directly and tightly focused on the cells for optoinjection, laser-induced stress waves, photochemical internalization, and irradiation of selective cell targeting with light-absorbing particles. During the past few years, extensive progress and numerous breakthroughs have been made in this area of research. This review covers four different laser-assisted transfection techniques and their advantages and disadvantages. Universality towards various cell lines is possibly the main advantage of laser-assisted optoporation in comparison with presently existing methods of cell transfection.

Chromophore-assisted light inactivation of pKi-67 leads to inhibition of ribosomal RNA synthesis

OBJECTIVES

Expression of the nuclear Ki-67 protein (pKi-67) is strongly associated with cell proliferation. For this reason, antibodies against this protein are widely used as prognostic tools for the assessment of cell proliferation in biopsies from cancer patients. Despite this broad application in histopathology, functional evidence for the physiological role of pKi-67 is still missing. Recently, we proposed a function of pKi-67 in the early steps of ribosomal RNA (rRNA) synthesis. Here, we have examined the involvement of pKi-67 in this process by photochemical inhibition using chromophore-assisted light inactivation (CALI).

MATERIALS AND METHODS

Anti-pKi-67 antibodies were labelled with the fluorochrome fluorescein 5(6)-isothiocyanate and were irradiated after binding to their target protein.

RESULTS

Performing CALI in vitro on cell lysates led to specific cross-linking of pKi-67. Moreover, the upstream binding factor (UBF) necessary for rRNA transcription was also partly subjected to cross-link formation, indicating a close spatial proximity of UBF and pKi-67. CALI in living cells, using micro-injected antibody, caused a striking relocalization of UBF from foci within the nucleoli to spots located at the nucleolar rim or within the nucleoplasm. pKi-67-CALI resulted in dramatic inhibition of RNA polymerase I-dependent nucleolar rRNA synthesis, whereas RNA polymerase II-dependent nucleoplasmic RNA synthesis remained almost unaltered.

CONCLUSIONS

Our data presented here argue for a crucial role of pKi-67 in RNA polymerase I-dependent nucleolar rRNA synthesis.

The Linderniaceae and Gratiolaceae are further lineages distinct from the Scrophulariaceae (Lamiales)

The Lamiales are one of the largest orders of angiosperms, with about 22,000 species. The Scrophulariaceae, as one of their most important families, has recently been shown to be polyphyletic. As a consequence, this family was re-classified and several groups of former scrophulariaceous genera now belong to different families, such as the Calceolariaceae, Plantaginaceae, or Phrymaceae. In the present study, relationships of the genera Craterostigma, Lindernia and its allies, hitherto classified within the Scrophulariaceae, were analyzed. Sequences of the chloroplast trnK intron and the matK gene (approximately 2.5 kb) were generated for representatives of all major lineages of the Lamiales and the former Scrophulariaceae. Bayesian and parsimony analyses revealed two isolated lineages, one of which consists of Lindernia and its allies, the other of Gratiola and allies. Gratiola was previously assumed to be related to Lindernia and was therefore included here. It is proposed to treat the two clades as separate families, Linderniaceae and Gratiolaceae. For the Linderniaceae, several morphological synapomorphies exist in addition to molecular data, such as conspicuous club-shaped stamen appendages.

Inhibition of mitogen-activated protein kinase kinase induces apoptosis of human chondrocytes

We previously have reported that the mitogen-activated protein kinase (MAPK) pathway is stimulated by adhesion of human chondrocytes to anti-beta(1)-integrin antibodies or collagen type II in vitro. These mechanisms most likely prevent chondrocyte dedifferentiation to fibroblast-like cells and chondrocyte death. To investigate whether this pathway plays an essential role for the differentiation, phenotype, and survival of chondrocytes, we blocked mitogen-activated protein kinase/extracellular signal-regulated kinase (Erk) (MEK), a kinase upstream of the kinase Erk by using U0126. Exposure of chondrocytes to U0126 caused activation of caspase-3 in a dose-dependent manner. Western blot analysis with an antibody specific for dually phosphorylated Erk shows that collagen type II induced phosphorylation of Erk1/2 was specifically blocked by U0126 in a dose-dependent manner. Immunohistochemical analysis showed that treated chondrocytes were caspase-3 positive. In treated chondrocytes, the cleavage of 116-kDa poly(ADP-ribose)polymerase resulted in the 85-kDa apoptosis-related cleavage fragment and was associated with caspase-3 activity. Analysis by electron microscopy showed typical morphological signs of apoptosis, such as crescent-shaped clumps of heterochromatin, and a degraded pericellular matrix. Thus, these results indicate that the MEK/Erk signal transduction pathway is involved in the maintenance of chondrocytes differentiation and survival. These data stimulate further investigations on the role of mitogen-activated protein kinase pathways in human chondrocytes.

[Madreporic hydroxyapatite granulates for filling bone defects]

Two macrocrystalline madreporic granular hydroxyapatite implants of different size range (single crystal size within both implants 1-3 microns) were implanted for 7, 28, 84 and 168 days into the trabecular bone of the distal femur epiphysis of rabbits. Both materials were investigated histologically. For testing of granular materials a new animal model has been developed. The drill hole was closed by reimplantation of an autologeous chondrocortical tissue slice to prevent loss of particles into the knee-joint. Both of the granular materials tested developed increasing bone bonding from the 7th day on to outer surfaces and pore surfaces. The degradation of both of the materials affected the superficial implant layers in soft-tissue interfaces exclusively and was mainly due to passive processes, e.g. leaching, fragmentation of granules after crack-production, particulate degradation and subsequent phagocytosis of liberated implant particles by macrophages and foreign body giant cells. Zones of superficial implant degradation were bonded partially to bone a second time. A possible low-degree, active superficial degradation by foreign body giant cells is discussed. Osteoclasts of typical morphology as being observed on other hydroxyapatite implant surfaces were not demonstrated. This was related to the low degradation rate of the implants. Both of the granular materials tested are useful in filling bone defects. A guided tissue regeneration due to partial implant degradation and subsequent bone formation seems to be impossible since the degradation rate of the materials is too low.

Signal transduction by beta1 integrin receptors in human chondrocytes in vitro: collaboration with the insulin-like growth factor-I receptor

We have examined the mechanism by which collagen-binding integrins co-operate with insulin-like growth factor-I (IGF-I) receptors (IGF-IR) to regulate chondrocyte phenotype and differentiation. Adhesion of chondrocytes to anti-beta1 integrin antibodies or collagen type II leads to phosphorylation of cytoskeletal and signalling proteins localized at focal adhesions, including alpha-actinin, vinculin, paxillin and focal adhesion kinase (FAK). These stimulate docking proteins such as Shc (Src-homology collagen). Moreover, exposure of collagen type II-cultured chondrocytes to IGF-I leads to co-immunoprecipitation of Shc protein with the IGF-IR and with beta1, alpha1 and alpha5 integrins, but not with alpha3 integrin. Shc then associates with growth factor receptor-bound protein 2 (Grb2), an adaptor protein and extracellular signal-regulated kinase. The expression of the docking protein Shc occurs only when chondrocytes are bound to collagen type II or integrin antibodies and increases when IGF-I is added, suggesting a collaboration between integrins and growth factors in a common/shared biochemical signalling pathway. Furthermore, these results indicate that focal adhesion assembly may facilitate signalling via Shc, a potential common target for signal integration between integrin and growth-factor signalling regulatory pathways. Thus, the collagen-binding integrins and IGF-IR co-operate to regulate focal adhesion components and these signalling pathways have common targets (Shc-Grb2 complex) in subcellular compartments, thereby linking to the Ras-mitogen-activated protein kinase signalling pathway. These events may play a role during chondrocyte differentiation.

Tissue engineering of biphasic joint cartilage transplants

In isolated posttraumatic or idiopathic joint defects the chondral layers and adjacent subchondral spongy bone are usually destructed. For regeneration we suggest the in vitro formation of a cartilage-coated biomaterial carriers (biphases) in order to fill the correspondingjoint defects. In this study Biocoral, a natural coralline material made of calcium carbonate, and calcite, a synthetic calcium carbonate, were used as supports for the cultivation of bovine chondrocytes in a three-dimensional polymer fleece. The cell-polymer-structure was affixed to the biomaterial with a fibrin-cell-solution. The artificial cartilage formed a new matrix and fused with the underlying biomaterial. The results indicate a promising technical approach to anchor tissue engineered cartilage in joint defects.

Presence and distribution of collagen II, collagen I, fibronectin, and tenascin in rabbit normal and osteoarthritic cartilage

OBJECTIVE

To investigate changes in the composition of articular cartilage matrix during the development of experimental osteoarthritis (OA), collagen type II, collagen type I, and the noncollagenous proteins fibronectin and tenascin were studied in normal and osteoarthritic cartilage of rabbits.

METHODS

OA of the knee joint was induced by a medial meniscectomy and section of the medial collateral ligament and anterior cruciate ligament. Frozen sections of rabbit normal and OA cartilage were stained with monoclonal antibodies against collagen type II, collagen type I, fibronectin, and tenascin.

RESULTS

Collagen II manifested a decreased interterritorial staining and seemed to increase territorially in the deeper zones of the OA cartilage. Collagen I was found in normal cartilage as a thin layer covering the surface and also in OA fibrillated cartilage. Fibronectin was present in normal and OA cartilage. Whereas a layer covered the normal cartilage, a thicker layer was observed in OA cartilage. In addition, changes in fibronectin distribution from the pericellular to the interterritorial matrix were observed. Tenascin was also found in normal cartilage matrix, particularly in the territorial and interterritorial matrix of the deeper zones. It showed an increased staining intensity in fibrillated cartilage, in the pericellular matrix of the upper chondrocytes, and on the surface lining in OA cartilage.

CONCLUSION

Collagen type II deposition seems to increase in the deeper cartilage zones during the osteoarthritic process, as a sign of tissue repair response. Collagen type I, fibronectin, and tenascin show enhanced deposition in the upper, fibrillated osteoarthritic cartilage, suggesting a common mediator controlled pathway.

[Comparison of internal fixation methods for the symphysis in multi-directional dynamic gait simulation]

For the stabilization of the ruptured pubic symphysis, rigid forms of fixation such as plate osteosynthesis and flexible fixations such as wire loops or PDS banding have been recommended. All methods have only been tested by static unidirectional loading until failure of the system. By this experimental arrangement Ecke and Hofmann found comparable results for flexible and rigid methods of internal stabilization of the pubic symphysis. They preferred flexible methods to maintain mobility of the symphysis and to prevent symphyseal fusion. We tested dynamic compression plate osteosynthesis, reconstruction plate osteosynthesis, wire loops and PDS banding for internal fixation of injured pubic symphysis in a dynamic multidirectional experimental arrangement simulating gait conditions. The specimens were loaded with 85 N in vertical (y-) direction and 34 N in sagittal (z-) direction, which represent 50% of the forces acting at the pubic symphysis during walking and with a frequency of 1.5 Hz over 55,500 loads simulating the conditions over a 6-week mobilization period. Loading with 100% of the acting forces (corresponding to full weight bearing mobilization) led to early failure of the system. Our experimental analysis showed that neither wire loops nor PDS banding is able to stabilize the ruptured pubic symphysis, even immediately after fixation before loading. During the tests instability increased until failure of the system due to cutting of the bone or breaking of the wires or PDS banding. Success of plate osteosynthesis was dependent on the initial stability of the fixation. Overwinding of the screws, as in osteoporotic bone, lead to increasing loosening during repeated loading, whereas primary stable fixation of the screws was almost completely maintained during the test. In consequence, neither wire loops nor PDS banding should be used for stabilization of injured pubic symphysis if early mobilization with partial weight bearing is desired. Plate osteosynthesis (DC or reconstruction plate) tolerates early half weight bearing in patients with "open-book" injury only if safe screw fixation is guaranteed.

[Biomechanics of the pubic symphysis. Which forces lead to mobility of the symphysis in physiological conditions?]

For estimation of the loads of fixation devices, physiological movements and acting forces at the symphysis pubis are examined. Experimentally, Walheim determined the movements of the pubic symphysis under physiological conditions (one-leg stance, walking): there is no effective mobility in the horizontal direction. During the one-leg stance he observed symphyseal mobility of up to 2.6 mm (Phi 1.2 mm) in the vertical direction and 1.3 mm (Phi 0.6 mm) in the sagittal direction. During walking he found symphyseal mobility of up to 2.2 mm (Phi 0.9 mm) in the vertical direction and 1.3 mm (Phi 0.6 mm) in the sagittal direction. Until now the forces leading to symphyseal mobility have not been estimated either experimentally or mathematically. In our experimental study we examined ten fresh cadaver anterior pelvic rings by means of a multidirectional force-mobility measurement. Maximal physiological movements, as determined by Walheim, were increasingly induced in ten equal steps, and the forces required were measured for every single step. Out of the resulting force-mobility curves for the ten cadaver specimens the mean force required (with standard deviation) was calculated for each of the ten measure points, separately for the vertical (y-) direction and sagittal (z-) direction. The values were graphically transferred, and a regression curve was created. This curve allows the acting force to be estimated for every movement of the pubic symphysis: During the one-leg stance the mean force to induce mean mobility is 169 N in vertical direction and 148 N in sagittal direction; for maximal mobility a force of 398 N in the vertical direction and 148 N in the sagittal direction is necessary. During walking, the force required to induce mean movement of the symphysis pubis is 120 N in the vertical direction and 68 N in the sagittal direction; for maximal mobility 333 N is required in the vertical direction and 136 N in the sagittal direction. For mobilization of patients with a symphyseal rupture (type Tile B 1) with partial weight-bearing, neutralization of the mean acting forces during the one-leg stance (169 N in the vertical direction, 68 N in the sagittal direction) must be achieved by an adequate fixation device. In cases where full weight bearing is desirable, such as in patients with limited compliance, stability can only be reached by neutralization of the maximal acting forces during walking (333 N in the vertical direction, 136 N in the sagittal direction).

Relevance of carbohydrate-deficient transferrin as a predictor of alcoholism in intensive care patients following trauma

Every second traumatized patient is a chronic alcoholic. Chronic alcoholics are at risk due to an increased morbidity and mortality. Reliable and precise diagnostic methods for detecting alcoholism are mandatory to prevent posttraumatic complications by adequate prophylaxis. The patient's history, however, is often not reliable, and conventional laboratory markers are not sensitive or specific enough. The aim of this study was to investigate whether carbohydrate-deficient transferrin (CDT) is a sensitive and specific marker to detect alcoholism in traumatized patients. One hundred and five male traumatized patients or their relatives gave their written informed consent to participate in this institutionally approved study. All patients were transferred to the intensive care unit after admission to the emergency room, followed by surgical treatment. Diagnostics included an alcoholism-related questionnaire, conventional laboratory markers (mean corpuscular volume, gamma-glutamyltransferase, aspartate aminotransferase, and alanine aminotransferase), and CDT sampling (microanion-exchange chromatography, turbidimetry, and radioimmunoassay, respectively). Only patients in whom a reliable history could be obtained were included. Alcoholism was diagnosed if the patients met the Diagnostic and Statistical Manual of Mental Disorders criteria for chronic alcohol abuse or dependence. The administration of fluids before CDT sampling was carefully documented. Patients did not differ significantly regarding age, Trauma and Injury Severity Score, and Acute Physiology and Chronic Health Evaluation score. The sensitivity of the CDT research kit was 70% and of the commercially available kit CDTect was 65%. Early sampling in the emergency room and before administration of large volumes of fluid increased the sensitivity to 83% for the CDT research kit and 74% for CDTect, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

[Herpes simplex digitalis--an important differential diagnosis of paronychia]

Herpes simplex infection of the hand is often falsely diagnosed as a pyogenic paronychia or felon and treated as such, because the clinical picture is not known and pathogen isolation is difficult. However, the surgical treatment of herpes digitalis is contraindicated, since it promotes the development of superinfections and triggers recurrence. The pathogen can be isolated in cell cultures prepared from the vesicle contents or a smear from the vesicle base. Serological antibody testing is unreliable. Topical application of Acyclovir cream (Zovirax) is the treatment of choice.

Treatment of extensive aseptic defects in old Achilles tendon ruptures: methods and case reports

Defect bridging is still problematic in the secondary treatment of Achilles tendon ruptures. Smaller defects can be treated without problems by the well-known standardized methods, whereas other methods have to be applied for treating larger defects. Free transplants with autogenous or exogenous material should be mentioned in this context. Complications are more likely to occur with exogenous material, free transplants from the fascia lata require an additional intervention to remove the transplant from another localization. These methods cannot be applied to achieve reliable restoration of continuity for defects with a length of 10 cm. Therefore, in these special cases, we carry out the tendon transplantation with a free tendon-muscle graft from the triceps surae muscle. We achieved reliable restoration of continuity with complication-free healing of the free transplant in, up to now, three cases, in association with the formation of a strong, functionally high grade scar plate in the area of the tendon.

[Modified after care following primary management of rupture of the Achilles tendon]

During the period ranging from 1975 to 1988, 169 Achilles tendon ruptures were operated on in the Department of Traumatology and Reconstructive Surgery of Steglitz Medical Center, Free University of Berlin. The majority of these ruptures, i.e. 149 cases, were due to sports injuries. In order to comply with our patients' wish for quick rehabilitation, we have altered our follow-up treatment concept since 1982. The surgical technique remained the same in the form of a Bunnell suture with wire or absorbable suture material. There was an initial post-operative immobilization for five to seven days in a dorsal femoral plaster splint at a 30 degree bending position. The ankle joint was immobilized in a neutral position from the start. After approximately one week, the lower leg was put in a walking cast in a neutral position. The patients were allowed to put full load on the leg. After an additional four weeks, the cast was removed and functional follow-up treatment started. The two patient collectives that were compared did not significantly differ with regard to age structure and accident mechanisms or accident causes. Changes in the follow-up treatment resulted in a marked reduction in duration from 14 to 10 weeks. Standing on the toes was likewise possible after 10 weeks. Sports activities could be resumed after four instead of six months, as before. The postoperative rate of complications was low. There were only 10 infections in the total patient collective, one being a deep-wound infection requiring surgical intervention.(ABSTRACT TRUNCATED AT 250 WORDS)

[Surgical treatment of acromioclavicular joint injury]

The acromioclavicular joint plate according to Rahmanzadeh allows the safe retention of the reset acromioclavicular joint in stage Tossy III and in exceptional cases also in stage Tossy II traumata when simultaneous early functional post-treatment is done from the first postoperative day on. The clinical results obtained after follow-up examinations of 53 of the 83 patients treated in this way were mostly good or very good. Perfect radiological results were obtained in 50% of these patients; 40% showed a slight subluxation and 10% a marked but pain-free subluxation.

[Corrective osteotomy of the head of the tibia in primary and secondary gonarthrosis--a para-articular operation]

The corrective osteotomy at the head of the tibia with degenerative or posttraumatic medial or lateral gonarthrosis and misalignment of the axis is until today a procedure to be recommended prior to a total or partial implantation of an endoprosthesis. The main advantage in comparison with a mono-condylar prosthesis is the removal of the causal damage of the misalignment. Old age and general relative risks are no contraindications to this procedure. The method used most in the operative technique is the correction of valgus deviation at the head of the tibia after osteotomy of the fibula with stabilization with a fixateur externe. On the whole, the risk of the operation is very low, the main complication is the lesion of the nervus peronaeus. With regard to the subjective result from the patients point of view the most important aspect is the relief or disappearance of pain, which is reached in comparison with a partial prosthesis of the knee joint with similar security. About two thirds of the patients are subjectively contempt with the results of the operation within a time of three to five years.

[Plate osteosynthesis of forearm fractures in adults and adolescents. Long-term results and problems]

Based on the results reported in the literature, the method applied by us in the management of forearm shaft fractures is presented and explained. The advantages and remaining problems of the method are discussed on the basis of the results obtained in the follow-up of 45 ulna-, radius- or forearm shaft fractures treated by means of DC-plate osteosynthesis. The procedure is complication-free and has a low pseudarthrosis rate. To avoid refractures, the material should not be removed earlier than one and a half year following osteosynthesis. Axis shifts of more than 10 degrees and differences in length of more than 2 mm should be avoided and should be corrected in working patients.

Adjuvant fosfomycin medication in chronic osteomyelitis

The therapeutic effectiveness of adjuvant therapy with fosfomycin was studied in a prospective clinical trial of 60 patients suffering from chronic post-traumatic osteomyelitis. The patients were aged between 17 and 78 years (mean 37.4 years). The chronic osteomyelitis was predominantly located in the tibia (43 patients) and in the femur (13 patients). Most of the pathogens isolated were Staphylococcus aureus (42%), coagulase-negative staphylococci (19%), Pseudomonas aeruginosa (12%), streptococci (7%) and enterococci (5%). The pathogens isolated from the osteomyelitic foci were sensitive to fosfomycin. Fosfomycin concentrations in bone samples were determined in 19 patients. In the group of patients receiving initially 5 g fosfomycin, bone concentrations ranged between 119.4 and 451.2 mg/l of interstitial fluid. In the group of patients receiving initially 10 g fosfomycin, bone concentrations ranged between 117.1 and 3684.2 mg/l of interstitial fluid. The mean MIC90 values of the isolated pathogens ranged between 2 and 64 mg/l (S. aureus and Escherichia coli 2 mg/l, Proteus vulgaris 8 mg/l, streptococci groups A and B 32 mg/l and coagulase-negative staphylococci, enterococci and P. aeruginosa 64 mg/l). The outcome of treatment was assessed after a minimum of seven and a maximum of 53 months (mean 37 months). The results were: very good 54.7%, good 3.8%, satisfactory 15.1% and unsatisfactory 26.4%.