Sequence-directed dynamic covalent assembly of base-4-encoded oligomers.

As an information-bearing biomacromolecule, DNA is encoded in base-4, where each residue site can be occupied by any one of four nucleobases. Mimicking the information dense, sequence-selective hybridization of DNA, we demonstrate two orthogonal dynamic covalent interactions to effect the selective assembly of molecular ladders and grids from base-4-encoded oligo(peptoid)s.

Biological and Mechanical Evaluation of Novel Prototype Dental Composites.

The breakdown of the polymeric component of contemporary composite dental restorative materials compromises their longevity, while leachable compounds from these materials have cellular consequences. Thus, a new generation of composite materials needed to be designed to have a longer service life and ensure that any leachable compounds are not harmful to appropriate cell lines. To accomplish this, we have developed concurrent thiol-ene-based polymerization and allyl sulfide-based addition-fragmentation chain transfer chemistries to afford cross-linked polymeric resins that demonstrate low shrinkage and low shrinkage stress. In the past, the filler used in dental composites mainly consisted of glass, which is biologically inert. In several of our prototype composites, we introduced fluorapatite (FA) crystals, which resemble enamel crystals and are bioactive. These novel prototype composites were benchmarked against similarly filled methacrylate-based bisphenol A diglycidyl ether dimethacrylate / triethylene glycol dimethacrylate (bisGMA/TEGDMA) composite for their cytotoxicity, mechanical properties, biofilm formation, and fluoride release. The leachables at pH 7 from all the composites were nontoxic to dental pulp stem cells. There was a trend toward an increase in total toughness of the glass-only-filled prototype composites as compared with the similarly filled bisGMA/TEGDMA composite. Other mechanical properties of the glass-only-filled prototype composites were comparable to the similarly filled bisGMA/TEGDMA composite. Incorporation of the FA reduced the mechanical properties of the prototype and bisGMA/TEGDMA composite. Biofilm mass and colony-forming units per milliliter were reduced on the glass-only-filled prototype composites as compared with the glass-only-filled bisGMA/TEGDMA composite and were significantly reduced by the addition of FA to all composites. Fluoride release at pH 7 was greatest after 24 h for the bisGMA/TEGDMA glass + FA composite as compared with the similarly filled prototypes, but overall the F- release was marginal and not at a concentration to affect bacterial metabolism.

In situ deprotection and dynamic covalent assembly using a dual role catalyst.

Utilization of constituent molecular precursors bearing covalently coreactive functional groups for self-assembly risks premature reaction, impeding synthetic and purification efforts. To prevent premature amine-aldehyde condensation for oligomers bearing both groups, we employ a dual-role Lewis acid catalyst for both in situ acetal deprotection and subsequent imine exchange, effecting oligomer assembly.

Oxygen-Mediated Enzymatic Polymerization of Thiol-Ene Hydrogels.

Materials that solidify in response to an initiation stimulus are currently utilized in several biomedical and surgical applications; however, their clinical adoption would be more widespread with improved physical properties and biocompatibility. One chemistry that is particularly promising is based on the thiol-ene addition reaction, a radical-mediated step-growth polymerization that is resistant to oxygen inhibition and thus is an excellent candidate for materials that polymerize upon exposure to aerobic conditions. Here, thiol-ene-based hydrogels are polymerized by exposing aqueous solutions of multi-functional thiol and allyl ether PEG monomers, in combination with enzymatic radical initiating systems, to air. An initiating system based on glucose oxidase, glucose, and Fe2+ is initially investigated where, in the presence of glucose, the glucose oxidase reduces oxygen to hydrogen peroxide which is then further reduced by Fe2+ to yield hydroxyl radicals capable of initiating thiol-ene polymerization. While this system is shown to effectively initiate polymerization after exposure to oxygen, the polymerization rate does not monotonically increase with raised Fe2+ concentration owing to inhibitory reactions that retard polymerization at higher Fe2+ concentrations. Conversely, replacing the Fe2+ with horseradish peroxidase affords an initiating system is that is not subject to the iron-mediated inhibitory reactions and enables increased polymerization rates to be attained.

Low vitamin D level is associated with higher relapse rate in natalizumab treated MS patients.

BACKGROUND: Previous research suggested a relationship between low vitamin D and relapse rate. We examined whether vitamin D levels were associated with: 1) MS severity and 2) recent MS relapse activity, in patients treated with natalizumab. METHODS: All patients (n=118) were treated with natalizumab and were tested for vitamin D levels during the winter of 2009-10. Number of relapses during treatment with natalizumab was determined by retrospective chart review. MS severity was estimated with the Roxburgh's MS Severity Score (MSSS) at the time of the initial blood draw and 1 year preceding and following initial draws. Vitamin D levels of 50 nmol/L or greater were defined as normal. RESULTS: Patients with deficient vitamin D levels (DVD) totaled 45. Sixteen of the 26 patients with relapse in the year prior to the initial blood draw (4 patients had multiple relapses - all were in DVD) and 12 of 17 patients with relapse in the following year were in the DVD group. There was a significant difference between the normal vitamin D group (NVD) and DVD in MS relapse activity in the year prior (p=0.005) and following blood draw (p=0.006). There was no significant between group differences in MSSS at any time. CONCLUSIONS: Natalizumab treated patients with DVD were more likely to experience relapse and may experience more relapses than patients with NVD.

The CombiRx trial of combined therapy with interferon and glatiramer acetate in relapsing remitting MS: Design and baseline characteristics.

BACKGROUND: Interferon-ß1a (IFNB) and glatiramer acetate (GA) are distinct therapies which are both partially effective for relapsing MS. It is not known if combining the two treatments would be more effective. OBJECTIVE: To review the rationale, design, and baseline characteristics of the CombiRx study of combined treatment with IFNB and GA. METHODS: The key inclusion criteria included a diagnosis of relapsing MS, at least 2 episodes of MS activity in the previous 3 years, expanded disability status scale of 0-5.5, and no prior treatment with either IFNB or GA. Subjects were randomized to IFNB+GA, IFNB monotherapy, or GA monotherapy in a 2:1:1 ratio. RESULTS: From 2005 to 2009, we enrolled 1008 subjects. The participants were 72.4% female and 87.6% Caucasian with a mean age of 37.7 years. The median duration of symptoms was 2 years at entry into the study, and the mean EDSS was 2.1. On the baseline MRI, the mean total lesion load was 12.2ml, and 40% of the participants had enhancing lesions. CONCLUSION: We have recruited a population of patients with clinical and MRI characteristics typical for early MS. The study results will aid in deciding on the optimum early treatment. This trial should serve as a model for future studies of combination therapy.

Evidence-based guideline: clinical evaluation and treatment of transverse myelitis: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.

OBJECTIVE: To assess the evidence for diagnostic tests and therapies for transverse myelitis (TM) and make evidence-based recommendations. METHODS: A review of the published literature from 1966 to March 2009 was performed, with evidence-based classification of relevant articles. RECOMMENDATIONS: Level B recommendations: neuromyelitis optica (NMO)-immunoglobulin G (IgG) antibodies should be considered useful to determine TM cause in patients presenting with clinical acute complete transverse myelitis (ACTM) features. The presence of NMO-IgG antibodies (aquaporin-4-specific antibodies) should be considered useful in determining increased TM recurrence risk. Level C recommendations: in suspected TM, distinction between ACTM or acute partial transverse myelitis may be considered useful to determine TM etiology and risk for relapse (more common with APTM). Age and gender may be considered useful to determine etiology in patients presenting with TM syndrome, with spinal infarcts seen more often in older patients and more female than male patients having TM due to multiple sclerosis (MS). Brain MRI characteristics consistent with those of MS may be considered useful to predict conversion to MS after a first partial TM episode. Longer spinal lesions extending over >3 vertebral segments may be considered useful in determining NMO vs MS. CSF examination for cells and oligoclonal bands may be considered useful to determine the cause of the TM syndrome. Plasma exchange may be considered in patients with TM who fail to improve after corticosteroid treatment. Rituximab may be considered in patients with TM due to NMO to decrease the number of relapses. Level U recommendations: there is insufficient evidence to support or refute the efficacy of other TM therapies or the usefulness of ethnicity to determine the cause of a subacute myelopathy.

Functional system scores provide a window into disease activity occurring during a multiple sclerosis treatment trial.

BACKGROUND: Average expanded disability status scale (EDSS) score on entry into pivotal trials of multiple sclerosis (MS) therapies lies between 2 and 3. These lower EDSS levels are determined by functional system score (FSS). OBJECTIVE: We examined contributions of each FSS to characterization of MS patients at entry to and exit from the pivotal trial of intramuscular interferon ß-1a (IM IFN-ß-1a), as well as contribution of changes in FSS to changes in EDSS. METHODS: We reviewed FSS and EDSS data collected at 6-month examinations during the IM IFN-ß-1a pivotal trial (n = 286). To describe which functional systems were most affected by disease, we used an FSS cutoff of ≥ 2 (mild to moderate impairment) and defined sustained progression as a ≥ 1 point change in EDSS score or FSS being maintained for 6 months. RESULTS: The most frequently involved functional systems at baseline (FSS level of ≥ 2) were cerebellar (38%), pyramidal (37%), and sensory (34%). While all functional systems were affected to some extent by progressing MS, these FSSs were also most often affected at study end, with pyramidal and cerebellar FSSs being the greatest contributors to sustained EDSS progression. Treatment effect with IM IFN-ß-1a was most strongly seen in the pyramidal system. CONCLUSION: In this trial, some FSSs contributed more to detection of progression than others. While changes in lower EDSS were heavily weighted by the pyramidal FSS, all of the FSSs appeared to be important in understanding the overall impact of MS progression, demonstrating the responsive nature of the widely utilized EDSS.

Results of the Avonex Combination Trial (ACT) in relapsing-remitting MS.

OBJECTIVE: To assess the safety, tolerability, and efficacy of interferon beta-1a (IFNbeta-1a) combined with methotrexate (MTX), i.v. methylprednisolone (IVMP), or both in patients with relapsing-remitting multiple sclerosis (RRMS) with continued disease activity on IFNbeta-1a monotherapy. METHODS: Eligibility criteria included RRMS, Expanded Disability Status Scale score 0-5.5, and > or = 1 relapse or gadolinium-enhancing MRI lesion in the prior year on IFNbeta-1a monotherapy. Participants continued weekly IFNbeta-1a 30 microg i.m. and were randomized in a 2 x 2 factorial design to adjunctive weekly placebo or MTX 20 mg p.o., with or without bimonthly IVMP 1,000 mg/day for 3 days. The primary endpoint was new or enlarged T2 lesion number at month 12 vs baseline. The study was industry-supported, collaboratively designed, and governed by an investigator Steering Committee with independent Advisory and Data Safety Monitoring committees. Study operations, MRI analyses, and aggregated data were managed by an academic coordinating center. RESULTS: The 313 participants had clinical and MRI characteristics typical of RRMS. Combinations of IFNbeta-1a with MTX or IVMP were generally safe and well tolerated. Although trends suggesting modest benefit were seen for some outcomes for IVMP, the results did not demonstrate significant benefit for either adjunctive therapy. The data suggested IVMP reduced anti-IFNbeta neutralizing antibody titers. CONCLUSIONS: This trial did not demonstrate benefit of adding low-dose oral methotrexate or every other month IV methylprednisolone to interferon beta-1a in relapsing-remitting multiple sclerosis.

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 IFNbeta-1a) combined with methotrexate (MTX) and/or IV methylprednisolone (IVMP) in relapsing-remitting multiple sclerosis (RRMS) patients with continued disease activity on IM IFNbeta-1a monotherapy. METHODS: Eligibility criteria included RRMS, Expanded Disability Status Scale score 0-5.5, and >or=1 relapse or gadolinium-enhancing MRI lesion in the prior year while on IM IFNbeta-1a monotherapy. Subjects continued IFNbeta-1a 30 mcg IM weekly and were randomized in a 2 x 2 factorial design to adjunctive weekly placebo or MTX 20 mg PO, with or without IVMP 1,000 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-IFNbeta 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.

Gene expression changes in peripheral blood mononuclear cells from multiple sclerosis patients undergoing beta-interferon therapy.

OBJECTIVE: Multiple sclerosis (MS) is a disabling idiopathic inflammatory disorder with evidence of immune dysfunction. Current therapies for MS include preparations of beta-interferon (beta IFN). We studied the gene expression patterns in peripheral blood mononuclear cells from relapsing-remitting MS patients undergoing weekly beta IFN-1a therapy (Avonex; 30 mg intramuscular) to identify biomarkers for beta IFN responsiveness. METHODS: Oligonucleotide microarrays were used for the comparative analysis of gene expression patterns from longitudinal PBMC samples taken from five patients undergoing beta IFN therapy. RESULTS: On the basis of two-fold changes in expression levels and statistical analyses we selected a candidate diagnostic set of 136 genes that were differentially expressed between pretreatment and IFN-beta-1a-treated MS patients. When we applied this gene set to cluster the specimens according to their expression profiles, the pretreatment samples clustered in one branch, and acute and chronic samples following treatment clustered in another branch. However, the chronic samples from the single clinical non-responder clustered with the pretreatment branch, suggesting that a possible reversal of beta IFN-induced gene expression may be contributing to the poor clinical response. CONCLUSIONS: These 136 genes represent potential targets for new MS therapeutics and the basis for lack of beta IFN response.

Morphology and gelation of thermosensitive chitosan hydrogels.

The morphology of physical hydrogels is often difficult to examine due to the delicate nature of the system and therefore has not been studied in detail. Chitosan/GP (glycerophosphate salt) is a significant hydrogel in the biomedical and cosmetic fields as it is thermosensitive and contains less than 5% polysaccharide. The morphology of this system was examined with laser scanning confocal microscopy (LSCM) to image the gel morphology. The images indicate that the gel is quite heterogeneous, and power spectra reveal a fractal-like morphology. A study of composition found that increasing chitosan concentration increased the amount of polymer-rich phase present in the gel, and that the smallest aggregates decreased in size.

Colonization and maintenance of murine embryonic stem cells on poly(alpha-hydroxy esters).

The aim of this study was to determine the ability of various poly(alpha-hydroxy esters) to support the in vitro propagation of murine embryonic stem (ES) cells in an undifferentiated state. To this end, ES cell colonization, growth and Oct-4 immunoreactivity following a 48 h culture period upon poly((D,L)-lactide), poly((L)-lactide), poly(glycolide) and poly((D,L)-lactide-co-glycolide) (PLGA) were assessed. By the analysis of live and dead cell number indices and Oct-4 immunoreactivity, ES cell colonization rate during a 48 h culture period was found to be significantly greater on PLGA compared to all the other unmodified poly(alpha-hydroxy esters) tested. Surface treatment of all polymers with 0.1m potassium hydroxide revealed a significant increase in ES cell live numbers when compared to all unmodified polymers, thus revealing a correlation between polymer content, hydrophilicity and colonization rate. These data suggest that surface treated poly(alpha-hydroxy esters) may be employed for ES cell scale up procedures and in tissue engineering applications requiring the colonization of scaffolds by ES cells in an undifferentiated state. According to such applications, once the designated scaffold has been colonized, ES cell directed differentiation into the desired and fully differentiated, functional adult tissue may then be effected.

Short-term prognosis in early relapsing-remitting multiple sclerosis.

OBJECTIVE: To characterize a group of patients with early MS using prognostic factors and to determine whether these prognostic factors impact on short-term prognosis. METHODS: Data were collected prospectively on 98 patients newly diagnosed with MS in our MS clinic between 1990 and 1998 (average follow-up, 37 months from the time of onset of clinically definite MS [CDMS]). Six prognostic factors were recorded: age at onset, symptoms at onset, MRI status at onset and at diagnosis of CDMS, interval between the first and second attack, attack frequency in the first 2 years, and completeness of recovery from initial attacks. Completeness of recovery was determined using Expanded Disability Status Scale scores (EDSS). Progression was determined by final EDSS and changes in EDSS between initial presentation and final follow-up. RESULTS: Patients predicted to have low risk of progression of MS based on the prognostic factors represented 17% of our patient population (0 to 1 risk factor for progression). The patients with high risk of progression (4 to 6 risk factors) represented 24% of patients. Patients with a high number of risk factors did significantly worse than those with a small or medium number of risk factors in terms of final EDSS and progression to higher EDSS. At the time of diagnosis of CDMS, MRI findings suggestive of MS were seen in 84% of patients (suspicious in 13%, negative in 3%). CONCLUSION: Short-term prognosis was influenced by the presence or absence of a high number of these six risk factors.

Shunt-responsive dementia in sarcoid meningitis: role of magnetic resonance imaging and cisternography.

The authors report a patient with progressive cognitive and gait decline in association with sarcoid meningitis. The patient had evidence of active inflammation as determined by cerebrospinal fluid examination and was steroid dependent. Magnetic resonance imaging and radionucleotide cisternography were complementary in establishing the diagnosis of communicating hydrocephalus, and suggested that the patient would be shunt responsive.

Cerebral herniation after lumbar puncture in sarcoid meningitis.

A patient with chronic meningitis due to neurosarcoidosis became comatose within minutes of a lumbar puncture and died 24 h later. The diagnosis of neurosarcoidosis was made post mortem. Development of cerebral herniation may have been exacerbated by lumbar puncture. It was proposed that arachnoid villi dysfunction may have contributed to very high intracranial pressures in this patient, since post mortem examination revealed communication between the ventricles and outlet foramina of the fourth ventricle, and that herniation was in part due to an acute pressure differential caused by lumbar puncture.

Transverse myelitis. Comparison with spinal cord presentations of multiple sclerosis.

We delineated the clinical and laboratory features that help distinguish acute myelopathic MS (MMS) from acute transverse myelitis (ATM), specifically testing the hypothesis that the symmetry of motor and sensory impairments at presentation can reliably distinguish between ATM and MMS. We reviewed 20 consecutive patients with ATM and 16 patients with MMS. Clinical criteria were used to assign patients to the ATM group. Patients assigned to the MMS group had onset of MS symptoms referable to the spinal cord and eventually fulfilled Poser's criteria for MS. The relative contribution of the symmetry of both motor and sensory symptoms for the accurate identification of ATM versus MMS was evaluated using a discriminant function analysis. Fifteen of 16 MMS patients and all 20 ATM patients presented with symptoms of motor dysfunction. Additionally, all patients in both groups presented with sensory complaints. MMS patients had asymmetric motor or sensory symptoms in all but one patient, whereas ATM patients exhibited symmetric weakness uniformly and symmetric sensory loss in all but one patient (statistically significant). None of the MS patients met criteria for ATM at presentation. None of the ATM patients developed MS over an average follow-up period of 4.5 years. In conclusion, MMS was easily distinguished from ATM in this study.

Magnetic resonance appearance of cerebral lymphomatoid granulomatosis.

Lymphomatoid granulomatosis is an angiocentric lymphoproliferative process that involves the lungs. In a 52-year-old-man with lymphomatoid granulomatosis who presented with encephalopathy, magnetic resonance imaging (MRI) of the brain demonstrated unusual multiple areas of enhancement that were both punctate and linear. These findings may be relatively specific for inflammation of deep cerebral vessels and have implications for MRI findings in other inflammatory cerebrovascular disorders.

Characterization of major depression symptoms in multiple sclerosis patients.

Retrospective review of affective disturbances in 238 patients with multiple sclerosis (MS) seen over a 6-month period revealed: 1) 51 patients (22%) received pharmacologic treatment for depressive symptoms during or within 4 years of the study period, and 17 (7%) received treatment for rapid mood swings; 2) among the 51 depressed patients, response rate to medication was extremely high; 3) relapse of depressive symptomatology after discontinuation of medication was also high (17/29); 4) first episodes of major depression frequently occurred during periods of MS progression or exacerbation, but first episodes also occurred during periods of relative clinical stability; 5) suicidal ideation was common (12 patients), but only 1 patient had a history of attempted suicide; and 6) side effects were tolerable in most patients.

Measurement of treatment response to sertraline in depressed multiple sclerosis patients using the Carroll scale.

We studied 11 patients with stable multiple sclerosis (MS) with major depression in terms of response to Sertraline at 100 mg q.d. in an open label trial. Patients were evaluated with self assessment measurements (Carroll scale) prior to and during treatment. Only one patient discontinued the drug during the three month treatment trial, and this was due to perceived lack of efficacy by the patient. The remainder of the patients completed at least three months of treatment and had significant improvement in depressive symptoms by self assessment measurements. No patients experienced side effects. Sertraline appears to be well tolerated and effective in treatment of major depression in MS. The Carroll scale is an easily administered means of assessing treatment response, and correlated highly with our clinical impressions.