Characterizing multiple sclerosis disease progression using a combined structural and functional connectivity metric

PURPOSE

A combined resting state functional connectivity MRI (fcMRI) and diffusion tensor imaging (DTI) metric called structural and functional connectivity index (SFCI) was recently proposed for tracking disease status and progression in multiple sclerosis (MS). The metric combines fcMRI and transverse diffusivity (TD) along different functional pathways involved in principle symptomatic domains of MS. In a longitudinal study of patients with MS receiving the same MS therapy, initial worsening of transcallosal (TC) motor and frontoparietal (FP) cognitive networks, as measured by fcMRI and DTI over the first year was followed by stabilization in the second year of follow-up. In this study we have (i) probed relationships between individual and composite neurological measures of MS with SFCI and its individual components along TC motor and FP cognitive pathways and (ii) compared sensitivity of SFCI to treatment-induced longitudinal changes with each individual imaging measure.

METHODS

Twenty five patients with MS (15 female, age 42 ± 8 y) participated in this study and were scanned at 3 T whole body MRI scanner with diffusion tensor imaging (DTI) and resting-state functional connectivity MRI (fcMRI) scan protocol at baseline and 6, 12, 18 and 24 months after starting fingolimod. fcMRI and TD along TC and FP pathways were combined to form structural and functional connectivity index (SFCI) at each time point. Correlations between individual/combined neurological measures and individual imaging components/SFCI at baseline and were evaluated and compared. In addition, efficacies of individual and combined imaging metrics in tracking network integrity were compared.

RESULTS

Individual TD along the TC pathway was significantly inversely correlated with all individual/composite neurological scores. There were moderate correlations of TC and FP components of SFCI with most of the neurological scores, and the pathway-combined SFCI was significantly correlated with all neurological scores. Trend-level increases of both TC and FP fcMRI were observed during the second year of follow-up, both TC and FP TD increased significantly in the first year and then stabilized during the second year. A trend toward a decrease in combined imaging metrics along TC and FP were observed during the first year, followed by a trend toward an increase in these metrics during the second year, while a significant decrease in SFCI during the first year followed by a significant increase during the second year was observed.

CONCLUSIONS

SFCI was more effective in tracking network integrity/disease progression than individual pathway-specific components, which supports its use as an imaging marker for MS disease status and progression.

118 Sustained reduction of disability and cognitive decline with long-term siponimod in EXPAND active SPMS patients

Background

In the EXPAND study, patients with active SPMS (aSPMS) demonstrated a reduced risk of 3/6-month confirmed disability progression (3m/6m CDP) and risk of decline in cognitive processing speed (CPS, 6-month confirmed cognition worsening of ≥4-point on Symbol Digit Modalities Test [6mCCW]) versus placebo.

Objectives

Assess long-term efficacy and safety of siponimod in patients with aSPMS.

Methods

In aSPMS patients who entered the EXPAND Extension, time to 3m/6mCDP, 6mCCW, and annu- alized relapse rate (ARR) were assessed for the Continuous (siponimod in Core and Extension) and Switch (placebo in Core and open-label siponimod in Core/Extension) groups.

Results

Risk of 6mCDP was reduced by 29% (0.71 [0.57–0.90]; p=0.0044) for Continuous versus Switch group, corresponding to approximately 70% delay in time to 6mCDP. The risk of 6mCCW for Continuous versus Switch group was reduced by 33% (0.67 [0.53–0.86]); p=0.0018), corresponding to approximately 70% delay in time to 6mCCW. A significant reduction in ARR for the Continuous versus Switch groups was observed in patients with or without active disease.

Conclusions

Long-term data analyses showed that siponimod effects on disability, cognitive processing speed, and relapse outcomes in patients with active SPMS are sustained up to 5 years, and highlight the value of early treatment initiation.

teresa.sawtell@novartis.com

114 Effect of siponimod on cognitive processing speed in SPMS patients with active and non-active disease

Background

Siponimod significantly reduced the relative risk of 3-month (m) confirmed disability progression (CDP) by 21% and 6mCDP by 26% versus placebo in the EXPAND core study and showed significant benefits on cognitive processing speed (CPS) using the Symbol Digit Modalities Test (SDMT).

Objectives

To evaluate the effect of siponimod on CPS in active (aSPMS) and non-active (naSPMS) patients from EXPAND core study.

Methods

This subgroup analysis included aSPMS patients (siponimod, n=516; placebo, n=263) and naSPMS patients (siponimod, n=557; placebo, n=270). Change in SDMT score; time to 6m confirmed ≥4-points cognitive worsening/improvement (6mCW/6mCI) on SDMT and the proportion of patients with worsened, stable and improved SDMT scores at M24 were analysed.

Results

Change in SDMT (95% Cl) versus placebo from baseline to M24 in aSPMS and naSPMS groups was

2.34 (0.66; 4.02) and 2.44 (0.67; 4.22), respectively, consistent with overall EXPAND core population. In aSPMS patients, siponimod reduced risk of 6mCW by 27% (p=0.06) and improved chances of 6mCI by 62% (p=0.007) versus placebo. Corresponding values in the naSPMS group were: 6mCW, 24% (p=ns) and 6mCI, 19% (p=ns).

Conclusions

Siponimod was associated with relevant benefits in CPS as measured by change in SDMT in patients with active and non-active SPMS.

teresa

sawtell@novartis.com

82

An evaluation of the Chesapeake Bay management strategy to improve water quality in small agricultural watersheds

Chesapeake Bay water quality has been a concern since 1970. In rural areas, agriculture is the dominant N and P source, and the voluntary application of best management practices (BMPs) is the primary management tool. Here we test the hypothesis that the current management approach of primarily voluntary, untargeted BMP implementation is insufficient to create detectable, widespread reductions in N, P, and total suspended solid (TSS) concentrations in agricultural watersheds of the Choptank basin, a tributary of Chesapeake Bay. To test this hypothesis, we assessed BMP implementation and sampled water quality on participating farms, at intermediate streams within each watershed, and at watershed outlets of four watersheds from 2013 to 2014. We also present water quality data from 2003 to 2014 at the outlets of 12 additional agricultural and one forested watershed and survey-directed interviews of farmers. By the end of 2014, large numbers of BMPs, both structural and cultural, had been implemented. Of the 16 agricultural watersheds, 50% showed significant decreases in baseflow N, 37.5% showed no changes, and 12.5% showed increasing TN. Baseflow P significantly decreased at just one watershed, increased at one, and remained stable at 14. Stormflow N was similar to baseflow, but stormflow P was 5 times higher than baseflow. These data partially support our hypothesis. Surveys suggested farmers considered themselves responsible for the quality of water leaving their farms, but out-of-pocket cost was the major impediment to further BMP adoption. We suggest that greater outreach and more financial support for farmers to implement BMPs is required to increase the types and densities of BMPs needed to achieve regional water quality goals.

Understanding the Efficiency of Splenic Hemangiosarcoma Diagnosis Using Monte Carlo Simulations

Hemangiosarcoma is a common neoplasm of the spleen in older dogs. However, diagnosis is complicated by necrosis and hemorrhage, which can mimic a number of benign processes. Currently, there is no consensus about the number of sections pathologists should examine to rule out hemangiosarcoma. To answer this question, we examined 413 histopathologic sections from 50 cases of canine hemangiosarcoma (mean: 8.1 sections per case; range, 5-14). Each section had the presence or absence of hemangiosarcoma determined by 2 board-certified anatomic pathologists. Then, 100 Monte Carlo simulations were performed, randomly selecting sections from each case 10 000 times and the results averaged. These simulations suggest that examination of 5 sections from a spleen with hemangiosarcoma yields a 95.02% chance of diagnosing hemangiosarcoma, while examination of 10 sections yields a 98.59% chance of diagnosis when hemangiosarcoma is in fact present. The data emphasize the need to submit the entire spleen for histopathologic examination in suspected cases of hemangiosarcoma and suggest that 5 sections obtained by a trained individual are likely sufficient for diagnosis.

Symptomatic Vertebral Hemangioma of the Posterior Elements Sharing Blood Supply with a Radiculomedullary Artery

Vertebral hemangiomas are common lesions usually restricted to the vertebral body. They are characterized by proliferation of endothelial cells and subsequent expansion of vascular spaces within the bone. These lesions are usually clinically silent and are discovered incidentally. Only rarely are vertebral hemangiomas symptomatic. Here, we present the case of a 68-year-old female with an aggressive hemangioma causing neurologic deficit. The lesion was localized within the posterior spinal elements, with no involvement of the vertebral body. Transarterial embolization was deemed unsafe due to the close proximity of a prominent radiculomedullary artery. The patient was treated with posterior decompression at T4-T6.

Strategy To Prepare 3-Bromo- and 3-Chloropyrazoles

A general strategy to prepare substituted 3-bromo- and 3-chloropyrazoles is described. The three-step method involves condensation of crotonates or β-chloro carboxylic acids with hydrazines, followed by halogenation and oxidation. Several condensation and oxidation protocols were developed to enable preparation of a wide variety of 3-halopyrazoles with good to excellent yields and regiocontrol.

Effect of delayed-release dimethyl fumarate on no evidence of disease activity in relapsing-remitting multiple sclerosis: integrated analysis of the phase III DEFINE and CONFIRM studies

BACKGROUND AND PURPOSE

Significant effects on clinical/neuroradiological disease activity have been reported in patients with relapsing-remitting multiple sclerosis treated with delayed-release dimethyl fumarate (DMF) in phase III DEFINE/CONFIRM trials. We conducted a post hoc analysis of integrated data from DEFINE/CONFIRM to evaluate the effect of DMF on achieving no evidence of disease activity (NEDA) in patients with relapsing-remitting multiple sclerosis.

METHODS

The analysis included patients randomized to DMF 240 mg twice daily, placebo or glatiramer acetate (CONFIRM only) for ≤2 years. A time-to-event method was used to estimate the percentage of patients achieving NEDA. Clinical NEDA (no relapses/no 12-week confirmed disability progression) was analysed in the intention-to-treat (ITT) population. Neuroradiological (no new/newly enlarging T2 hyperintense lesions/no gadolinium-enhancing lesions) and overall NEDA (clinical and neuroradiological NEDA) were analysed in the magnetic resonance imaging (MRI) cohort.

RESULTS

The ITT and MRI populations comprised 1540 and 692 patients, respectively. The percentage of patients with clinical NEDA (ITT population) and neuroradiological NEDA (MRI cohort) was higher with DMF versus placebo over 2 years [clinical NEDA: 38.9% relative reduction; hazard ratio (HR), 0.61; 95% confidence interval (CI), 0.52-0.72; P < 0.0001; neuroradiological NEDA: 40.0% relative reduction; HR, 0.60; 95% CI, 0.49-0.73; P < 0.0001]. The percentage of patients achieving overall NEDA (MRI cohort) was also higher with DMF (26%) versus placebo (12%) over 2 years, with a relative risk reduction of 42.7% (HR, 0.57; 95% CI, 0.48-0.69; P < 0.0001).

CONCLUSIONS

A significantly higher percentage of patients treated with DMF achieved NEDA status over 2 years compared with placebo.

Measuring Brain Tissue Integrity during 4 Years Using Diffusion Tensor Imaging

BACKGROUND AND PURPOSE

DTI is an MR imaging measure of brain tissue integrity. Little is known regarding the long-term longitudinal evolution of lesional and nonlesional tissue DTI parameters in multiple sclerosis and the present study examines DTI evolution over 4 years.

MATERIALS AND METHODS

Twenty-one patients with multiple sclerosis were imaged for up to 48 months after starting natalizumab therapy. Gadolinium-enhancing lesions at baseline, chronic T2 lesions, and normal-appearing white matter were followed longitudinally. T2 lesions were subclassified as black holes and non-black holes. Within each ROI, the average values of DTI metrics were derived by using Analysis of Functional Neuro Images software. The longitudinal trend in DTI metrics was estimated by using a mixed-model regression analysis.

RESULTS

A significant increase was observed for axial diffusivity (P < .001) in gadolinium-enhancing lesions and chronic T2 lesions during 4 years. No significant change in radial diffusivity either in normal-appearing white matter or lesional tissue was observed. The evolution of axial diffusivity was different in gadolinium-enhancing lesions (P < .001) and chronic T2 lesions (P = .02) compared with normal-appearing white matter.

CONCLUSIONS

An increase in axial diffusion in both gadolinium-enhancing lesions and T2 lesions may relate to the complex evolution of chronically demyelinated brain tissue. Pathologic changes in normal-appearing white matter are likely more subtle than in lesional tissue and may explain the stability of these measures with DTI.

Time course of clinical and neuroradiological effects of delayed-release dimethyl fumarate in multiple sclerosis

BACKGROUND AND PURPOSE

Delayed-release dimethyl fumarate (DMF, also known as gastro-resistant DMF), demonstrated efficacy and safety in relapsing-remitting multiple sclerosis in the 2-year, randomized, placebo-controlled, phase 3 DEFINE and CONFIRM trials. A post hoc analysis of integrated data from DEFINE and CONFIRM was conducted to determine the temporal profile of the clinical and neuroradiological effects of DMF.

METHODS

Eligible patients were randomized to receive placebo, DMF 240 mg twice (BID) or three times (TID) daily or glatiramer acetate (GA; reference comparator; CONFIRM only) for up to 96 weeks. Patients in the GA group were excluded from this analysis.

RESULTS

A total of 2301 patients were randomized and received treatment with placebo (n = 771) or DMF BID (n = 769) or TID (n = 761). DMF significantly reduced the annualized relapse rate beginning in weeks 0-12 (BID, P = 0.0159; TID, P = 0.0314); the proportion of patients relapsed beginning at week 10 (BID, P = 0.0427) and week 12 (TID, P = 0.0451); and the proportion of patients with 12-week confirmed disability progression beginning at week 62 (BID, P = 0.0454) and week 72 (TID, P = 0.0399), compared with placebo. These effects were sustained throughout the 2-year study period. DMF significantly reduced the odds of having a higher number of gadolinium-enhancing lesions by 88% (BID) and 75% (TID) and the mean number of new or enlarging T2 lesions by 72% (BID) and 67% (TID), from the first post-baseline magnetic resonance imaging assessment at 24 weeks (all P < 0.0001 versus placebo).

CONCLUSIONS

In phase 3 clinical trials, DMF demonstrated rapid and sustained clinical and neuroradiological efficacy in relapsing-remitting multiple sclerosis.

Fatal PML associated with efalizumab therapy: insights into integrin αLβ2 in JC virus control

OBJECTIVES

Progressive multifocal leukoencephalopathy (PML) has become much more common with monoclonal antibody treatment for multiple sclerosis and other immune-mediated disorders.

METHODS

We report 2 patients with severe psoriasis and fatal PML treated for ≥3 years with efalizumab, a neutralizing antibody to αLβ2-leukointegrin (LFA-1). In one patient, we conducted serial studies of peripheral blood and CSF including analyses of leukocyte phenotypes, migration ex vivo, and CDR3 spectratypes with controls coming from HIV-infected patients with PML. Extensive pathologic and histologic analysis was done on autopsy CNS tissue of both patients.

RESULTS

Both patients developed progressive cognitive and motor deficits, and JC virus was identified in CSF. Despite treatment including plasma exchange (PE) and signs of immune reconstitution, both died of PML 2 and 6 months after disease onset. Neuropathologic examination confirmed PML. Efalizumab treatment was associated with reduced transendothelial migration by peripheral T cells in vitro. As expression levels of LFA-1 on peripheral T cells gradually rose after PE, in vitro migration increased. Peripheral and CSF T-cell spectratyping showed CD8+ T-cell clonal expansion but blunted activation, which was restored after PE.

CONCLUSIONS

From these data we propose that inhibition of peripheral and intrathecal T-cell activation and suppression of CNS effector-phase migration both characterize efalizumab-associated PML. LFA-1 may be a crucial factor in homeostatic JC virus control.

(+)-Sorangicin A: evolution of a viable synthetic strategy

An effective, asymmetric total synthesis of the antibiotic (+)-sorangicin A (1) has been achieved. Central to this venture was the development of first and second generation syntheses of the signature dioxabicyclo[3.2.1]octane core, the first featuring chemo- and stereoselective epoxide ring openings facilitated by a Co(2)(CO)(6)-alkyne complex, the second involving a KHMDS-promoted epoxide ring formation/opening cascade. Additional highlights include effective construction of the dihydro- and tetrahydropyran ring systems, respectively via a stereoselective conjugate addition/α-oxygenation protocol and a thioketalization/hydrostannane reduction sequence. Late-stage achievements entailed two Julia-Kociénski olefinations to unite three advanced fragments with high E-stereoselectivity, followed by a modified Stille protocol to introduce the Z,Z,E trienoate moiety, thereby completing the carbon skeleton. Mukaiyama macrolactonization, followed by carefully orchestrated Lewis and protic acid-promoted deprotections that suppressed isomerization and/or destruction of the sensitive (Z,Z,E)-trienoate linkage completed the first, and to date only, total synthesis of (+)-sorangicin A (1).

A validation study of multicenter diffusion tensor imaging: reliability of fractional anisotropy and diffusivity values

BACKGROUND AND PURPOSE

DTI is increasingly being used as a measure to study tissue damage in several neurologic diseases. Our aim was to investigate the comparability of DTI measures between different MR imaging magnets and platforms.

MATERIALS AND METHODS

Two healthy volunteers underwent DTI on five 3T MR imaging scanners (3 Trios and 2 Signas) by using a matched 33 noncollinear diffusion-direction pulse sequence. Within each subject, a total of 16 white matter (corpus callosum, periventricular, and deep white matter) and gray matter (cortical and deep gray) ROIs were drawn on a single image set and then were coregistered to the other images. Mean FA, ADC, and longitudinal and transverse diffusivities were calculated within each ROI. Concordance correlations were derived by comparing ROI DTI values among each of the 5 magnets.

RESULTS

Mean concordance for FA was 0.96; for both longitudinal and transverse diffusivities, it was 0.93; and for ADC, it was 0.88. Mean scan-rescan concordance was 0.96-0.97 for all DTI measures. Concordance correlations within platforms were, in general, better than those between platforms for all DTI measures (mean concordance of 0.96).

CONCLUSIONS

We found that a 3T magnet and high-angular-resolution pulse sequence yielded comparable DTI measurements across different MR imaging magnets and platforms. Our results indicate that FA is the most comparable measure across magnets, followed by individual diffusivities. The comparability of DTI measures between different magnets supports the feasibility of multicentered clinical trials by using DTI as an outcome measure.

Measuring myelin repair and axonal loss with diffusion tensor imaging

BACKGROUND AND PURPOSE

DTI is an MR imaging measure of brain tissue integrity and provides an attractive metric for use in neuroprotection clinical trials. The purpose of our study was to use DTI to evaluate the longitudinal changes in brain tissue integrity in a group of patients with MS.

MATERIALS AND METHODS

Twenty-one patients with MS starting natalizumab were imaged serially for 12 months. Gadolinium-enhancing lesions and 20 regions of interest from normal-appearing white and gray matter brain tissue were followed longitudinally. Average values within each region of interest were derived for FA, λ(∥), λ(⊥), and MD. New T1 black holes were identified at 12 months. Analysis was performed by using mixed-model regression analysis with slope (ie, DTI change per month) as the dependent variable.

RESULTS

During 1 year, FA increased in gadolinium-enhancing lesions but decreased in NABT (P < .0001 for both). Changes in FA within gadolinium-enhancing lesions were driven by decreased λ(⊥) (P < .001), and within NABT, by decreased λ(∥) (P < .0001). A higher λ(⊥) within gadolinium-enhancing lesions at baseline predicted conversion to T1 black holes at 12 months. MD was unchanged in both gadolinium-enhancing lesions and NABT.

CONCLUSIONS

We observed changes in DTI measures during 1 year in both gadolinium-enhancing lesions and NABT. The DTI results may represent possible remyelination within acute lesions and chronic axonal degeneration in NAWM. These results support the use of DTI as a measure of tissue integrity for studies of neuroprotective therapies.

Total synthesis of (+)-sorangicin A

The final synthetic challenges associated with (+)-sorangicin A have been overcome, thus leading to the first total synthesis of this complex macrolide antibiotic. Highlights of the highly convergent synthesis include two Julia-Kociénski olefinations to unite three advanced fragments with high E-stereoselectivity. Critical to the final-stage success was the use of a carefully defined Stille coupling and a Mukaiyama macrolactonization as well as Lewis and protic acid-promoted deprotections carefully designed to suppress E/Z isomerization and/or destruction of the delicate (Z,Z,E)-trienoate linkage.

Effect of plasma exchange in accelerating natalizumab clearance and restoring leukocyte function

BACKGROUND

Accelerating the clearance of therapeutic monoclonal antibodies (mAbs) from the body may be useful to address uncommon but serious complications from treatment, such as progressive multifocal leukoencephalopathy (PML). Treatment of PML requires immune reconstitution. Plasma exchange (PLEX) may accelerate mAb clearance, restoring the function of inhibited proteins and increasing the number or function of leukocytes entering the CNS. We evaluated the efficacy of PLEX in accelerating natalizumab (a therapy for multiple sclerosis [MS] and Crohn disease) clearance and alpha4-integrin desaturation. Restoration of leukocyte transmigratory capacity was evaluated using an in vitro blood-brain barrier (ivBBB).

METHODS

Twelve patients with MS receiving natalizumab underwent three 1.5-volume PLEX sessions over 5 or 8 days. Natalizumab concentrations and alpha4-integrin saturation were assessed daily throughout PLEX and three times over the subsequent 2 weeks, comparing results with the same patients the previous month. Peripheral blood mononuclear cell (PBMC) migration (induced by the chemokine CCL2) across an ivBBB was assessed in a subset of six patients with and without PLEX.

RESULTS

Serum natalizumab concentrations were reduced by a mean of 92% from baseline to 1 week after three PLEX sessions (p < 0.001). Although average alpha4-integrin saturation was not reduced after PLEX, it was reduced to less than 50% when natalizumab concentrations were below 1 mug/mL. PBMC transmigratory capacity increased 2.2-fold after PLEX (p < 0.006).

CONCLUSIONS

Plasma exchange (PLEX) accelerated clearance of natalizumab, and at natalizumab concentrations below 1 mug/mL, desaturation of alpha4-integrin was observed. Also, CCL2-induced leukocyte transmigration across an in vitro blood-brain barrier was increased after PLEX. Therefore, PLEX may be effective in restoring immune effector function in natalizumab-treated patients.

Rapid magnetic resonance imaging-guided reduction of craniovertebral junction deformities

The authors demonstrate the utility of an MR imaging-compatible traction board for the rapid reduction of craniovertebral junction (CVJ) deformities. To choose the appropriate surgical management, patients with compressive CVJ deformities often undergo a trial of traction. Conventional traction trials require the treating surgeon to infer from plain radiographs the manner in which traction forces affect neural and ligamentous structures at the CVJ. To avoid overdistraction injury, low increments of weight are added in a gradual fashion, a process that typically requires 48-72 hours. The authors outline the use of an MR imaging-compatible traction board to determine reducibility safely and rapidly in 4 patients with compressive CVJ deformities. Four patients with advanced CVJ deformities underwent a trial of MR imaging-guided traction performed using an MR imaging-compatible spine board. Serial sagittal images were acquired at baseline and following each sequential addition of force. All patients tolerated traction without neurological worsening. The neural elements were seen to be adequately decompressed in all cases during a single MR imaging session. Patients subsequently underwent craniocervical stabilization and fusion. Postoperative imaging showed maintenance of the reduction without neural compression. An MR imaging-guided trial of traction can facilitate the rapid and safe determination of the reducibility of compressive lesions in patients with advanced CVJ deformities. Rapidly acquired sagittal MR images permit the surgeon to evaluate the effects of traction on the soft tissues at the CVJ, thereby expediting the traction trial and avoiding the risks of immobility in this often-fragile patient population.

Multiple sclerosis: chemokine receptor expression on circulating lymphocytes in correlation with radiographic measures of tissue injury

BACKGROUND

Leukocytes expressing inflammatory chemokine receptors (CKRs), most consistently CCR2, CCR5, and CXCR3, have been identified in multiple sclerosis (MS) tissue lesions and provide attractive therapeutic targets. Our previous studies found large inter-individual differences in expression of these CKRs but stable levels over time within subjects. This observation suggests a CKR "set-point" within individuals, which might relate to inflammatory injury in MS. We evaluated the correlation between CKR levels and magnetic resonance imaging (MRI) measures of disease activity.

METHODS

Fifty-five relapsing remitting MS (RRMS) and secondary progressive MS (SPMS) patients were prospectively followed with annual CKR and MRI studies. Multiparameter flow cytometry was used to determine CCR2, CCR5, and CXCR3 expression on CD4 and CD8 cells. Simultaneous cranial MRIs were performed, and quantitative measures of T2, T1, and gadolinium lesions, brain parenchymal fraction (BPF), and whole brain and fractionated magnetization transfer ratio (MTR) were performed using automated software. Spearman's rank correlations evaluated the relationship between CKR levels and MRI measures.

RESULTS

Significant correlations were observed between CXCR3 expression on CD8 cells and measures of new (T1) and total (T1, T2) lesion volumes, lesion MTR, and BPF; higher levels of CXCR3 expression were correlated with greater injury on MRI (|r| = 0.27-0.42). In contrast, CD4 cell CKR expression was only minimally correlated with MRI measures.

CONCLUSIONS

Over 2 years, we observed significant correlations between the percent of CD8 cells expressing CXCR3 and MRI measures of MS inflammatory activity and tissue destruction. These observations are consistent with a pathogenic role for cytotoxic T cells in MS brain and have significant implications regarding T-cell targeted therapeutic strategies.

Evolution of the Petasis-Ferrier union/rearrangement tactic: construction of architecturally complex natural products possessing the ubiquitous cis-2,6-substituted tetrahydropyran structural element

The frequent low abundance of architecturally complex natural products possessing significant bioregulatory properties mandates the development of rapid, efficient, and stereocontrolled synthetic tactics, not only to provide access to the biologically rare target but also to enable elaboration of analogues for the development of new therapeutic agents with improved activities and/or pharmacokinetic properties. In this Account, the genesis and evolution of the Petasis-Ferrier union/rearrangement tactic, in the context of natural product total syntheses, is described. The reaction sequence comprises a powerful tactic for the construction of the 2,6- cis-substituted tetrahydropyran ring system, a ubiquitous structural element often found in complex natural products possessing significant bioactivities. The three-step sequence, developed in our laboratory, extends two independent methods introduced by Ferrier and Petasis and now comprises: condensation between a chiral, nonracemic beta-hydroxy acid and an aldehyde to furnish a dioxanone; carbonyl olefination; and Lewis-acid-induced rearrangement of the resultant enol acetal to generate the 2,6- cis-substituted tetrahydropyranone system in a highly stereocontrolled fashion. To demonstrate the envisioned versatility and robustness of the Petasis-Ferrier union/rearrangement tactic in complex molecule synthesis, we exploited the method as the cornerstone in our now successful total syntheses of (+)-phorboxazole A, (+)-zampanolide, (+)-dactylolide, (+)-spongistatins 1 and 2, (-)-kendomycin, (-)-clavosolide A, and most recently, (-)-okilactomycin. Although each target comprises a number of synthetic challenges, this Account focuses on the motivation, excitement, and frustrations associated with the evolution and implementation of the Petasis-Ferrier union/rearrangement tactic. For example, during our (+)-phorboxazole A endeavor, we recognized and exploited the inherent pseudo symmetry of the 2,6- cis-substituted tetrahydropyranone product to overcome the inherent chelation bias of an adjacent oxazolidine ring during the Lewis-acid-promoted rearrangement. In addition, we discovered that a more concentrated solution of Cp2TiMe2 (0.7 versus 0.5 M in THF) with the addition of ethyl pivalate dramatically improves the yield in the Petasis-Tebbe olefination. During the (+)-zampanolide and (+)-dactylolide programs, we observed that the addition of trifluoromethanesulfonic acid (TfOH), especially on a preparative scale, was crucial to the efficiency of the initial condensation/union reaction, while our efforts toward (-)-kendomycin led to the improved implementation of a modified Kurihara condensation of the beta-hydroxy acid and aldehyde involving i-PrOTMS and TMSOTf. Finally, the successful deployment of the Petasis-Ferrier tactic in our synthesis of (-)-clavosolide A validated the viability of this tactic with a system possessing the highly acid-labile cyclopropylcarbinyl moiety, while the challenges en route to (-)-okilactomycin demonstrated that a neighboring alkene functionality can participate in an intramolecular Prins cyclization during the TMSOTf-promoted union process, unless suitably protected.

Avonex Combination Trial in relapsing—remitting MS: rationale, design and baseline data

Objective To review the rationale, design and baseline data of the Avonex Combination Trial (ACT), an investigator-run study of intramuscular interferon beta-1a (IM IFNβ-1a) combined with methotrexate (MTX) and/or IV methylprednisolone (IVMP) in relapsing—remitting multiple sclerosis (RRMS) patients with continued disease activity on IM IFNβ-1a monotherapy.

Methods Eligibility criteria included RRMS, Expanded Disability Status Scale score 0—5.5, and ≥1 relapse or gadolinium-enhancing MRI lesion in the prior year while on IM IFNβ-1a monotherapy. Subjects continued IFNβ-1a 30 mcg IM weekly and were randomized in a 2 × 2 factorial design to adjunctive weekly placebo or MTX 20 mg PO, with or without IVMP 1000 mg/day for three days every other month. ACT was industry-supported, and collaboratively designed and governed by an Investigator Steering Committee with independent Advisory and Data Safety Monitoring Committees. Study operations, MRI analysis and aggregated data were managed by the Cleveland Clinic MS Academic Coordinating Center.

Results In total 313 subjects were enrolled with clinical and MRI characteristics typical of RRMS. Most subjects (86.9%) qualified with a clinical relapse, with or without an enhancing MRI lesion, in the preceding year. At baseline, 21.4% had enhancing lesions, and 5.1% had anti-IFNβ neutralizing antibodies. ACT's management and operational structures functioned well.

Conclusion This study provides an innovative model for academic—industry collaborative MS research and will enhance understanding of the utility of combination therapy for RRMS patients with continued disease activity on an established first-line treatment. Multiple Sclerosis 2008; 14: 370—382. http://msj.sagepub.com

Enzyme optimization: moving from blind evolution to statistical exploration of sequence-function space

Directed evolution is a powerful tool for the creation of commercially useful enzymes, particularly those approaches that are based on in vitro recombination methods, such as DNA shuffling. Although these types of search algorithms are extraordinarily efficient compared with purely random methods, they do not explicitly represent or interrogate the genotype-phenotype relationship and are essentially blind in nature. Recently, however, researchers have begun to apply multivariate statistical techniques to model protein sequence-function relationships and guide the evolutionary process by rapidly identifying beneficial diversity for recombination. In conjunction with state-of-the-art library generation methods, the statistical approach to sequence optimization is now being used routinely to create enzymes efficiently for industrial applications.

Access to cerebrospinal fluid absorption sites by infusion into vascular channels of the skull diploë

Object

The purpose of this human cadaver study was to determine whether or not an intraosseous skull infusion would access the superior sagittal sinus (SSS) via intradural venous channels. The diploic space of the skull bone contains a sinusoidal vascular network that communicates with the underlying dura mater. Diploic veins in the parasagittal area connect with endothelium-lined intradural channels in the subjacent dura and ultimately with the dural venous sinuses. A significant proportion of cerebrospinal fluid (CSF) absorption is thought to occur via arachnoid granulations in the region of the SSS and especially along the parasagittal dura where arachnoid granulations are surrounded by intradural venous channels (lateral lacunae). The CSF is likely to be conducted from the subarachnoid space into the venous system via the fine intradural channels making up the lateral lacunae.

Methods

Infusion of vinyl acetate casting material into the diploic space of the human cadaveric skull resulted in complete filling of the lateral lacunae and SSS. Corrosion casting techniques and examination under magnification were used to characterize the anatomical connections between diploic spaces and dural venous sinuses.

Results

Corrosion casting, performed on five formalin-fixed cadavers, clearly showed the anatomical connections between the diploic infusion site and the venous sinuses in the underlying parasagittal dura where some of the CSF is thought to be absorbed.

Conclusions

The diploic vascular channels of the human skull may represent an indirect pathway into the dural venous sinuses. Intraosseous skull infusion may represent another possible strategy for diversion of CSF into the vascular system in the treatment of hydrocephalus.

Intraosseous infusion into the skull: potential application for the management of hydrocephalus

OBJECT

Hydrocephalus results from abnormal cerebrospinal fluid (CSF) volumes or flow patterns. The absorption of CSF is determined largely by pressures within veins and venous sinuses in the head and adjacent to the spine. Most surgical solutions for hydrocephalus involve diversion of excess CSF into alternative absorption sites, and most of these solutions are still suboptimal. The focus of this work has been to recreate more normal CSF absorption into the dural venous sinuses without having to directly access the superior sagittal sinus (SSS).

METHODS

Intraosseous skull infusion for the purpose of accessing the SSS and the systemic venous system was tested by experimental skull infusions of tracer fluids into living large animals (14 adult pigs). Compared with control injections into an ear vein, infusions into the skull through specially designed infusion devices had similar systemic absorption characteristics. This suggested that intraosseous skull infusion in a living large animal was successful in gaining access to the SSS and systemic venous system.

CONCLUSIONS

This study constitutes the first demonstration of the success of intraosseous skull infusion in gaining rapid access to the systemic venous system and it thus opens the possibility of using this strategy for diversion of CSF back into the intracranial venous system for the treatment of hydrocephalus.

Optimal reference population for the multiple sclerosis functional composite

A reference population is used when integrating the individual components of the Multiple Sclerosis Functional Composite (MSFC) into a single composite score. The choice of reference populations may have a significant impact on the resulting MSFC score, yet the impact of different reference populations has not been evaluated. We evaluated the impact of different reference populations when deriving the Multiple Sclerosis Functional Composite (MSFC) in a group of MS patients followed longitudinally for two years. Reference populations included the study population at baseline ( n = 60), a group of healthy controls ( n = 18) and the National MS Society Task Force reference population ( n = variable). We found that the choice of reference population had a significant impact on the resulting MSFC Z-score, sometimes compromising the statistical sensitivity to change over time. Our results suggest that longitudinal studies employing a multisystem composite Z-score should use a reference population with similar patients, which can most easily be achieved by using the baseline measures of the population under study. These results have significant implications to sample size estimates for longitudinal clinical studies and therapeutic trials. Multiple Sclerosis 2007; 13: 909—914. http://msj.sagepub.com

Improving catalytic function by ProSAR-driven enzyme evolution

We describe a directed evolution approach that should find broad application in generating enzymes that meet predefined process-design criteria. It augments recombination-based directed evolution by incorporating a strategy for statistical analysis of protein sequence activity relationships (ProSAR). This combination facilitates mutation-oriented enzyme optimization by permitting the capture of additional information contained in the sequence-activity data. The method thus enables identification of beneficial mutations even in variants with reduced function. We use this hybrid approach to evolve a bacterial halohydrin dehalogenase that improves the volumetric productivity of a cyanation process approximately 4,000-fold. This improvement was required to meet the practical design criteria for a commercially relevant biocatalytic process involved in the synthesis of a cholesterol-lowering drug, atorvastatin (Lipitor), and was obtained by variants that had at least 35 mutations.

A pilot study of magnetic resonance imaging-guided closed reduction of cervical spine fractures

STUDY DESIGN

We report on a prospective selective case series of 17 patients with cervical fracture-dislocations treated with closed reduction under MRI guidance.

OBJECTIVE

To demonstrate the safe and effective use of in-line axial traction in the reduction of cervical fracture-dislocations using MRI guidance.

SUMMARY OF BACKGROUND DATA

Closed reduction of the cervical spine for acute fracture-dislocations has been a traditional technique used for restoring vertebral alignment and providing neural element decompression. The safety of this technique has been questioned, with concerns of disc migration and overdistraction causing neurologic worsening cited as reasons to choose operative reduction and decompression as a safer option in some circumstances.

METHODS

Seventeen patients with fracture-dislocations of the subaxial cervical spine were given a trial of traction under MRI guidance between 1999 and 2003. The incidence of posteriorly herniated disc material was noted, and the diameter of the spinal canal at the injured level was recorded before and after traction.

RESULTS

All patients tolerated traction without neurologic worsening. Pretraction disc disruption was found in 15 of 17 (88.2%) of patients, with posterior herniation in 4 of 17 (23.5\%). Traction caused a return of herniated disc material toward the disc space in all cases. Canal dimensions improved in 11 of 17 patients, with canal diameter increasing by a factor of 1.1 to 3.0, with a mean improvement of 1.73. The process of reduction was observed to be a gradual one, with progressive, significant improvement in canal dimensions occurring before anatomic realignment. As distracting force was increased, sequential MRIs showed that canal dimensions did not diminish at any time in any patient.

CONCLUSIONS

MRI monitoring in closed cervical reduction is a useful research tool for this technique. Closed reduction appears to be safe as used in this preliminary study and is effective in achieving immediate spinal cord decompression.

A two-sample Bayesian t-test for microarray data

BACKGROUND

Determining whether a gene is differentially expressed in two different samples remains an important statistical problem. Prior work in this area has featured the use of t-tests with pooled estimates of the sample variance based on similarly expressed genes. These methods do not display consistent behavior across the entire range of pooling and can be biased when the prior hyperparameters are specified heuristically.

RESULTS

A two-sample Bayesian t-test is proposed for use in determining whether a gene is differentially expressed in two different samples. The test method is an extension of earlier work that made use of point estimates for the variance. The method proposed here explicitly calculates in analytic form the marginal distribution for the difference in the mean expression of two samples, obviating the need for point estimates of the variance without recourse to posterior simulation. The prior distribution involves a single hyperparameter that can be calculated in a statistically rigorous manner, making clear the connection between the prior degrees of freedom and prior variance.

CONCLUSION

The test is easy to understand and implement and application to both real and simulated data shows that the method has equal or greater power compared to the previous method and demonstrates consistent Type I error rates. The test is generally applicable outside the microarray field to any situation where prior information about the variance is available and is not limited to cases where estimates of the variance are based on many similar observations.

(+)-Sorangicin A Synthetic Studies. Construction of the C(1−15) and C(16−29) Subtargets

[structure: see text] Effective stereocontrolled syntheses of subtargets (-)-2 and (-)-4, comprising respectively the C(16-29) and C(1-15) tetrahydropyran and dihydropyran moieties of the potent antibiotic (+)-sorangicin A (1), have been achieved. The cornerstone for the synthesis of (-)-2 involved an aldol tactic exploiting 1,4-induction, followed in turn by an acid-mediated cyclization/ketalization and hydrosilane reduction promoted by TMSOTf, while construction of (-)-4 entailed a stereoselective conjugate addition/alpha-oxygenation sequence.

Construction of a C(30−38) Dioxabicyclo[3.2.1]octane Subtarget for (+)-Sorangicin A, Exploiting a Regio- and Stereocontrolled Acid-Catalyzed Epoxide Ring Opening

[reaction: see text] In this paper, we report assembly of the novel dioxabicyclo[3.2.1]octane subtarget (-)-2, comprising the signature structural element of the potent antibiotic (+)-sorangicin A (1). The synthesis was achieved in 15 steps (1.5% overall yield) via a series of acid-catalyzed epoxide ring openings. The first, facilitated by the complex of alkyne (+)-3 with Co(2)(CO)(8), proceeded in a highly regio- and stereoselective fashion.

MRI findings in Susac's syndrome

BACKGROUND

Susac syndrome (SS) is a self-limited syndrome, presumably autoimmune, consisting of a clinical triad of encephalopathy, branch retinal artery occlusions, and hearing loss. All three elements of the triad may not be present or recognized, and MR imaging is often necessary to establish the diagnosis.

OBJECTIVE

To determine the spectrum of abnormalities on MRI in SS.

METHODS

The authors reviewed the MR images of 27 previously unreported patients with the clinical SS triad, and 51 patients from published articles in which the MR images were depicted or reported.

RESULTS

All 27 patients had multifocal supratentorial white matter lesions including the corpus callosum. The deep gray nuclei (basal ganglia and thalamus) were involved in 19 (70%). Nineteen (70%) also had parenchymal enhancement and 9 (33%) had leptomeningeal enhancement. Of the 51 cases from the literature, at least 32 had callosal lesions. The authors could not determine the presence of callosal lesions in 18 of these patients, and only one was reported to have a normal MRI at the onset of encephalopathy.

CONCLUSIONS

The MR scans in SS show a rather distinctive pattern of supratentorial white matter lesions that always involve the corpus callosum. There is often deep gray matter, posterior fossa involvement, and frequent parenchymal with occasional leptomeningeal enhancement. The central callosal lesions differ from those in demyelinating disease, and should support the diagnosis of SS in patients with at least two of the three features of the clinical triad.

High-dose methylprednisolone for acute closed spinal cord injury--only a treatment option

BACKGROUND

A systematic review of the evidence pertaining to methylprednisolone infusion following acute spinal cord injury was conducted in order to address the persistent confusion about the utility of this treatment.

METHODS

A committee of neurosurgical and orthopedic spine specialists, emergency physicians and physiatrists engaged in active clinical practice conducted an electronic database search for articles about acute spinal cord injuries and steroids, from January 1, 1966 to April 2001, that was supplemented by a manual search of reference lists, requests for unpublished additional information, translations of foreign language references and study protocols from the author of a Cochrane systematic review and Pharmacia Inc. The evidence was graded and recommendations were developed by consensus.

RESULTS

One hundred and fifty-seven citations that specifically addressed spinal cord injuries and methylprednisolone were retrieved and 64 reviewed. Recommendations were based on one Cochrane systematic review, six Level I clinical studies and seven Level II clinical studies that addressed changes in neurological function and complications following methylprednisolone therapy.

CONCLUSIONS

There is insufficient evidence to support the use of high-dose methylprednisolone within eight hours following an acute closed spinal cord injury as a treatment standard or as a guideline for treatment. Methylprednisolone, prescribed as a bolus intravenous infusion of 30 mg per kilogram of body weight over fifteen minutes within eight hours of closed spinal cord injury, followed 45 minutes later by an infusion of 5.4 mg per kilogram of body weight per hour for 23 hours, is only a treatment option for which there is weak clinical evidence (Level I- to II-1). There is insufficient evidence to support extending methylprednisolone infusion beyond 23 hours if chosen as a treatment option.

Acute, chronic, and recurrent varicella zoster virus neuropathy without zoster rash

The authors report three patients with acute, chronic, and recurrent neuropathy associated with varicella zoster virus (VZV) infection but without zoster rash. CSF of all three patients contained VZV immunoglobulin G antibody, but not herpes simplex virus. In two patients, serum/CSF ratios of VZV immunoglobulin G were reduced compared to normal ratios for immunoglobulin G and albumin, and one patient also had VZV immunoglobulin M in CSF. All three patients received antiviral therapy and improved. The diagnosis of nervous system infection by VZV may be confirmed by the presence of antibody to VZV in CSF even without detectable VZV DNA.

Aphemia: an isolated disorder of articulation

Aphemia is a disorder with prominent speech abnormality. Since its description by Broca, there has been debate regarding the neuropsychological disorganization underlying aphemia: is aphemia an articulatory disorder or a language disorder? We describe a patient with markedly impaired articulation, but preserved receptive and written language function and buccal-facial coordination. The location of his stroke was in the left precentral gyrus, undercutting a small area of motor and premotor cortex. This case suggests that aphemia can occur as an isolated articulation deficit without language involvement or more widespread bulbar apraxia, and may be a severe form of apraxia of speech.

Multiple sclerosis: the importance of early recognition and treatment

Primary practitioners need to know how to expedite the diagnosis and treatment of multiple sclerosis (MS), because treatments that can slow its course appear to be most effective when started early. Several lines of evidence demonstrate that tissue damage occurs very early in the disease, and much of this damage is clinically silent.

The Compass Elbow Hinge: indications and initial results

The Compass Elbow Hinge uses Illizarov's methods of fixation to externally hold the elbow reduced and allow both passive and active motion. Eleven patients with degenerative disease, contracture or instability were treated with the Compass Elbow Hinge and were retrospectively evaluated at an average follow-up of 29 months (range: 18-62 months). One was lost to follow-up. Patients with degenerative changes underwent fascia lata interposition while those treated for contractures underwent anterior and posterior capsular release with or without fascia lata interposition. Those with elbow instability underwent ligament reconstruction. The device was removed after 6 weeks and seven of the 11 patients were satisfied with the outcome of the operation. Stability could not be achieved in two patients with coronoid fractures that were not reconstructed. One patient did not tolerate the device and requested its removal with subsequent subluxation. We conclude that patient selection and compliance are key elements in achieving a satisfactory outcome with the device.