Dosing via gavage or diet for reproduction studies: a pilot study using two fat-soluble compounds-hexachlorobenzene and aroclor 1254

The choice of a dosing route for in vivo toxicological tests is often dictated by practical constraints. Reproduction studies are particularly challenging in this regard since the determination of no-effect levels and allowable daily intakes from reproduction data encompasses exposure of the dam to the test xenobiotic prior to pregnancy, during gestation and during lactation. The fetus/infant can be exposed to the xenobiotic as well as the dam's metabolic products of the test xenobiotic during gestation and lactation. We initiated a series of two-litter, pilot reproduction studies with Sprague-Dawley and Fischer 344 rats to specifically ascertain the amount of xenobiotic and its metabolites ingested by the nursing neonate on lactation days 4, 7, 12, 17 and 21, when its dam received the xenobiotic via its diet or by gavage. The xenobiotics studied in this initial series of experiments were hexachlorobenzene (HCB) and Aroclor(R) 1254 (polychlorinated biphenyls; PCBs). The dams were dosed for 28 days, mated to untreated males and then remated approximately 2 weeks after weaning their first litter to a second untreated male. Dietary levels of 10 ppm HCB or 10 ppm PCBs, and gavage doses of 0.9 mg HCB or 0.8 mg PCBs/kg body weight/day were chosen and resulted in similar doses of HCB and PCBs per unit of the body weight of the dam during the premating period. There were no apparent toxicological effects regarding the dam nor were any of the reproduction parameters (feed consumption, dam weight, litter size, pup weight, external anomalies and day 4 viability index) significantly different from control values. Following impregnation, the body weight of the dam increased appreciably during gestation, but its feed consumption increased only slightly. During lactation, the dam's feed consumption increased markedly while its body weight increased slightly. Consequently, when dams received the xenobiotic in their diet they consumed slightly less xenobiotic per unit of body weight during gestation when compared to the gavaged dams, whereas the situation was dramatically reversed during lactation. While the greater consumption of xenobiotic by the dietary-dosed dams during lactation did result in more HCB (P</=0.0001 for both litters) and PCBs/metabolites (litter one: P=0.05; litter two: P</=0.0001) in the suckling neonate's stomach contents in both generations, there was no evidence of any differences between the two litters when each sampling date was assessed separately, except for the day 4-HCB results when the litter one pups had more HCB in their stomachs (P=0.018). For the PCBs, the F344 neonates were found to have more PCBs in their stomachs (litter one P=0.0015; litter two P=0.002) than the Sprague-Dawley neonates. In addition, the amount of HCB, PCBs and fat in the neonates' stomachs decreased during lactation, as the pups age increased (P</=0.035). These preliminary results suggest that analogous amounts of HCB and PCBs given via diet or gavage may not result in similar lactational exposure by the suckling neonate.

Factors associated with health care utilization in pediatric multiple sclerosis

BACKGROUND

We assessed whether clinical characteristics and health-related quality of life (HRQOL) are independently associated with subsequent hospitalizations and physician visits among children with multiple sclerosis (MS); and whether differences in HRQOL account for differences in physician visits between children with MS, monophasic acquired demyelinating syndromes (ADS) and healthy children.

METHODS

We used linked administrative (health) data from Ontario, Canada and data from a prospective cohort study including HRQOL (measured using the PedsQL), age, sex, cognitive function (accuracy and response time as assessed by Penn Neurocognitive Battery), number of relapses, and neurologic abnormalities on examination. We used generalized linear models with generalized estimating equations to examine factors associated with hospitalizations and ambulatory physician visit rates following each HRQOL assessment, adjusting for age, sex, and socioeconomic status.

RESULTS

We included 36 children with MS, 43 with monophasic ADS and 43 healthy controls. Among children with MS, more relapses were associated with increased odds of hospitalization (odds ratio 1.59; 1.18-2.14); better cognitive accuracy scores were associated with fewer physician visits (rate ratio [RR] 0.68; 0.47-0.98). Children with MS had higher rates of physician visits than healthy children (RR 1.44; 1.00-2.08), unlike children with a monophasic ADS, but HRQOL scores did not account for these differences.

CONCLUSION

Within the MS population, more relapses are associated with increased odds of hospitalization while better cognitive performance is associated with reduced rates of physician visits. Differences in HRQOL do not account for differences in physician visits by children with MS as compared to healthy children.

Temporal profile of lymphocyte counts and relationship with infections with fingolimod therapy in paediatric patients with multiple sclerosis: Results from the PARADIGMS study

BACKGROUND

Reduction in absolute lymphocyte count (ALC) is expected with fingolimod treatment.

OBJECTIVE

To evaluate the effect of fingolimod 0.5 mg versus intramuscular interferon β-1a (30 μg) on ALC and its relationship with infections in paediatric-onset multiple sclerosis (POMS) up to 4 years.

METHODS

We assessed ALC at baseline, monthly till 3 months, and every 3 months (core phase) and with variable periodicity (extension phase) of Phase 3 PARADIGMS study (N = 215). Incidence rates (IRs) of infection-related adverse events (^infAEs)/100 patient-years were analysed by on-study nadir ALC.

RESULTS

With fingolimod, ALC rapidly reduced to 29.9%-34.4% of baseline values within 2 weeks and remained stable thereafter; no relevant changes observed with interferon. IRs of ^infAEs were 67.6 with fingolimod and 61.8 with interferon; IR ratios with respect to interferon, overall: 1.09, by nadir ALC 0.2-0.4 × 10⁹/L: 1.13 and >0.4 × 10⁹/L: 0.91. Three patients had a single episode of ALC <0.2 × 10⁹/L (core phase). No opportunistic infections were observed and infection risk did not increase during the extension phase.

CONCLUSION

In paediatric patients, the overall incidence of infections was comparable between fingolimod and interferon. No association was observed between nadir ALC and infections in POMS, although sample size may have been too small to rule an association.

Unusual imaging findings in progressive myoclonus epilepsy

We describe a patient with progressive myoclonus epilepsy (PME), white matter hyperintensities in the corpus callosum, cerebral hemispheres, and left cerebral peduncle on magnetic resonance imaging (MRI), and positive oligoclonal bands. A phosphorus magnetic resonance spectrum was compatible with mitochondrial dysfunction. Abnormal white matter signals are not a feature of the known PME syndromes, although they occur in Leber's hereditary optic neuropathy (LHON). These abnormalities oriented the diagnosis toward mitochondrial disease.

Evolving role of MRI in optimizing the treatment of multiple sclerosis: Canadian Consensus recommendations

Background

Magnetic resonance imaging (MRI) is increasingly important for the early detection of suboptimal responders to disease-modifying therapy for relapsing–remitting multiple sclerosis. Treatment response criteria are becoming more stringent with the use of composite measures, such as no evidence of disease activity (NEDA), which combines clinical and radiological measures, and NEDA-4, which includes the evaluation of brain atrophy.

Methods

The Canadian MRI Working Group of neurologists and radiologists convened to discuss the use of brain and spinal cord imaging in the assessment of relapsing–remitting multiple sclerosis patients during the treatment course.

Results

Nine key recommendations were developed based on published sources and expert opinion. Recommendations addressed image acquisition, use of gadolinium, MRI requisitioning by clinicians, and reporting of lesions and brain atrophy by radiologists. Routine MRI follow-ups are recommended beginning at three to six months after treatment initiation, at six to 12 months after the reference scan, and annually thereafter. The interval between scans may be altered according to clinical circumstances.

Conclusions

The Canadian recommendations update the 2006 Consortium of MS Centers Consensus revised guidelines to assist physicians in their management of MS patients and to aid in treatment decision making.

Proton magnetic resonance spectroscopy in brain white matter disorders

The advent of magnetic resonance imaging (MRI) has revolutionized the clinical approach to the evaluation of brain white matter disorders and has contributed significantly to expansion of the concept of these diseases. MRI is very sensitive at detecting white matter lesions, but conventional T1 and T2-weighted images do not provide specific pathological information about the lesions, and correlation between MRI lesion load and clinical disability is often weak. Proton magnetic resonance spectroscopy can provide chemical-pathological information of a given tissue in vivo. The use of this MR technique in brain white matter disorders has shown to improve diagnostic classification and to provide surrogate measures useful for monitoring disease evolution and response to therapeutic intervention.

Safety and efficacy of daclizumab beta in patients with relapsing multiple sclerosis in a 5-year open-label study (EXTEND): final results following early termination

Background:

EXTEND (NCT01797965), an open-label extension study, evaluated the safety and efficacy of daclizumab beta in participants with relapsing multiple sclerosis (MS) who had completed the randomized DECIDE study.

Methods:

Eligible participants who received either daclizumab beta or interferon beta-1a in DECIDE received daclizumab beta 150 mg subcutaneously every 4 weeks for up to 5 years in EXTEND, followed by 24 weeks of post-dosing follow-up. Safety and tolerability were evaluated, as were clinical efficacy and magnetic resonance imaging (MRI). EXTEND was terminated ahead of schedule by the sponsors.

Results:

The total safety population (N = 1203) received at least one dose of daclizumab beta in EXTEND. In the DECIDE and EXTEND combined periods, the median number of doses of daclizumab beta was 53; median time on treatment was 196 weeks. By 24 September 2018, the end of the study, 110/1203 (9%) participants had completed the protocol-specified treatment period and 1101/1203 (92%) had experienced an adverse event (AE). The most commonly reported AEs were MS relapse, nasopharyngitis, and upper respiratory tract infection. Hepatic events (18%), cutaneous events (45%), and infections (62%) were common treatment-related AEs. The incidence of serious AEs was 29%, most commonly MS relapse and infections. The incidence of immune-mediated disorders was 2%; three of seven were encephalitis. Two of six deaths were considered treatment related. In participants who received continuous daclizumab beta throughout DECIDE and EXTEND, the treatment effects on clinical and MRI outcomes were maintained for up to 6 years.

Conclusion:

Results from the combined DECIDE-EXTEND study elucidate outcomes of longer-term treatment with daclizumab beta in the clinical trial setting and underscore the importance of pharmacovigilance with immunomodulatory therapies in the real-world setting.

The place of MRI in monitoring the individual MS patient

Evidence of focal white matter inflammation on MRI can be related to relapses and chronic disability. The strength of the relationship depends on the stage of the disease. The predictive value is stronger early in the course of MS, when the focal white matter lesions are more important in the pathogenesis of MS. As the disease progresses, the predictive value of white matter lesions weakens and measures related to other, more diffuse aspects of the disease strengthen. Thus, lesion activity on MRI can be helpful as a guide to therapy, particularly early in the disease. Appropriate MRI criteria for a suboptimal response to therapy are not clear and may depend on the therapy being evaluated. The fact that diffuse pathology tends to progress despite effective suppression of focal inflammation is a cause for concern and needs to be addressed with new approaches to therapy that are more effective against this aspect of the disease.

No evidence for impairment of venous hemodynamics in children or young adults with pediatric-onset multiple sclerosis

BACKGROUND AND PURPOSE

Chronic cerebrospinal venous insufficiency is a postulated etiologic factor for multiple sclerosis, but the higher frequency with longer disease duration and progressive disability suggests that chronic cerebrospinal venous insufficiency is secondary to chronic disease. We evaluated the presence of chronic cerebrospinal venous insufficiency in pediatric-onset MS.

MATERIALS AND METHODS

Twenty-six pediatric patients with MS (18 years of age or younger), 26 age-matched healthy controls, and 13 young adults with pediatric-onset MS underwent sonography of the internal jugular, vertebral, and deep cerebral veins. Five venous hemodynamic criteria were assessed, with 2 criteria required for chronic cerebrospinal venous insufficiency. MR imaging studies, performed in the pediatric patients with MS and healthy control groups, included intracranial 2D time-of-flight MR venography and velocity-sensitive phase-contrast sequences. Contrast-enhanced brain MR images were obtained in pediatric patients with MS to further evaluate venous patency. We used paired t tests, Wilcoxon matched pairs, McNemar tests, and exact conditional logistic regression to estimate the association of chronic cerebrospinal venous insufficiency with MS.

RESULTS

Fifty participants (73.5%) had normal ultrasound findings, 15 (23.1%) met 1 venous hemodynamic criterion, and 2 pediatric patients with MS and 1 young adult with pediatric-onset MS met chronic cerebrospinal venous insufficiency criteria. Chronic cerebrospinal venous insufficiency was not associated with MS (odds ratio, 2.41; 95% CI, 0.19-infinity). Demographic and disease characteristics did not differ between the patients with MS meeting chronic cerebrospinal venous insufficiency criteria (n = 3) and those who did not (n = 36; all, P > .05). The mean (SD) MR imaging measures of intracerebral flow did not differ between the 2 pediatric patients with MS meeting chronic cerebrospinal venous insufficiency criteria (0.85 ± 0.11) and healthy controls (0.87 ± 0.16, P = .50); no child demonstrated venous obstruction.

CONCLUSIONS

Chronic cerebrospinal venous insufficiency is rarely observed in children or young adults with pediatric-onset MS. Venous anatomy and flow rates indicate that venous outflow is intact in pediatric patients with MS. Our findings argue against chronic cerebrospinal venous insufficiency as a component of MS etiology.

Delineation of cortical pathology in multiple sclerosis using multi-surface magnetization transfer ratio imaging

The purpose of our study was to evaluate the utility of measurements of cortical surface magnetization transfer ratio (csMTR) on the inner, mid and outer cortical boundaries as clinically accessible biomarkers of cortical gray matter pathology in multiple sclerosis (MS). Twenty-five MS patients and 12 matched controls were recruited from the MS Clinic of the Montreal Neurological Institute. Anatomical and magnetization transfer ratio (MTR) images were acquired using 3 Tesla MRI at baseline and two-year time-points. MTR maps were smoothed along meshes representing the inner, mid and outer neocortical boundaries. To evaluate csMTR reductions suggestive of sub-pial demyelination in MS patients, a mixed model analysis was carried out at both the individual vertex level and in anatomically parcellated brain regions. Our results demonstrate that focal areas of csMTR reduction are most prevalent along the outer cortical surface in the superior temporal and posterior cingulate cortices, as well as in the cuneus and precentral gyrus. Additionally, age regression analysis identified that reductions of csMTR in MS patients increase with age but appear to hit a plateau in the outer caudal anterior cingulate, as well as in the precentral and postcentral cortex. After correction for the naturally occurring gradient in cortical MTR, the difference in csMTR between the inner and outer cortex in focal areas in the brains of MS patients correlated with clinical disability. Overall, our findings support multi-surface analysis of csMTR as a sensitive marker of cortical sub-pial abnormality indicative of demyelination in MS patients.

•

Novel cortical MTR analysis identifies areas of sub-pial abnormality in MS patients.

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A greater area of sub-pial abnormality in MS exists on the outer cortical layer.

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Cortical regions most affected were involved in executive function and processing speed.

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Normalized differences between outer and inner cortex MTR correlate with EDSS in MS.

•

This technique can be applied for clinical trials at the MRI field strength of 3 T.

Physical activity and dentate gyrus volume in pediatric acquired demyelinating syndromes

Objective

To assess the association between daily moderate-to-vigorous physical activity (MVPA) and dentate gyrus volume (DGv) in pediatric patients with acquired demyelinating syndromes (ADSs) of the CNS.

Methods

Cross-sectional analysis of accelerometry (7 days) and research protocol MRI data from 12 pediatric MS and 18 children with monophasic ADS (monoADS). Total brain and DGv were quantified using standardized methods. The association of daily minutes of MVPA with normalized DGv (nDGv) was assessed using multivariable generalized linear models.

Results

Median (interquartile range) MVPA was lower in MS patients [9.5 (14)] and exhibited less variation than in monoADS patients [24.5 (47)]. nDGv did not differ significantly between groups [mean nDGv (SD) [cm³]: MS 0.34 (0.1); monoADS 0.4 (0.1); p = 0.100]. In the monoADS group, every 1-minute increase in MVPA was associated with a 2.4-mm³ increase in nDGv (p = 0.0017), an association that was independent of age at incident demyelination, time from incident demyelination, sex, and brain white matter T2 lesion volume. No significant association was found between MVPA and nDGv (−2.6 mm³/min, p = 0.16) in the MS group.

Conclusions

Higher MVPA associates with greater nDGv in children who have recovered from monophasic demyelination. Larger studies are required to determine whether MVPA can promote regional brain development, or limit tissue damage, in youth with MS.

The relation of focal white matter signal abnormality and focal volume loss in multiple sclerosis

There were two aims to this study. First, to explore how the reduction in the volume of abnormal T2-signal intensity associated with white matter (WM) lesions in multiple sclerosis (MS) relates to tissue loss resulting from focal pathology inside lesions. Second, to demonstrate that this volume of abnormal T2-signal intensity underestimates the actual size of the region to which the direct effects of lesion activity extend. For these purposes, we used deformation field analysis to quantify the evolution of local atrophy associated with a chronic peri-ventricular lesion in a patient with secondary progressive MS. This subject had particular features that may not necessarily co-exist in a group of unselected patients, which enabled interesting observations to be made. We show, quantitatively, that the focal WM lesion was associated with adjacent regional WM volume loss, which was disproportionate to concurrent diffuse atrophy in the rest of the normal appearing brain tissue, and that the loss of volume associated with the lesion was partially reciprocated by local ventricular expansion. Our observations re-emphasise the complex relationship between the change in the volume of abnormal signal intensity on magnetic resonance images and the tissue volume change directly related to lesion pathology. Multiple Sclerosis 2007; 13: 809-813. http:// msj.sagepub.com

Single-timepoint low-dimensional characterization and classification of acute versus chronic multiple sclerosis lesions using machine learning

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease characterized by the appearance of focal lesions across the central nervous system. The discrimination of acute from chronic MS lesions may yield novel biomarkers of inflammatory disease activity which may support patient management in the clinical setting and provide endpoints in clinical trials. On a single timepoint and in the absence of a prior reference scan, existing methods for acute lesion detection rely on the segmentation of hyperintense foci on post-gadolinium T1-weighted magnetic resonance imaging (MRI), which may underestimate recent acute lesion activity. In this paper, we aim to improve the sensitivity of acute MS lesion detection in the single-timepoint setting, by developing a novel machine learning approach for the automatic detection of acute MS lesions, using single-timepoint conventional non-contrast T1- and T2-weighted brain MRI. The MRI input data are supplemented via the use of a convolutional neural network generating "lesion-free" reconstructions from original "lesion-present" scans using image inpainting. A multi-objective statistical ranking module evaluates the relevance of textural radiomic features from the core and periphery of lesion sites, compared within "lesion-free" versus "lesion-present" image pairs. Then, an ensemble classifier is optimized through a recursive loop seeking consensus both in the feature space (via a greedy feature-pruning approach) and in the classifier space (via model selection repeated after each pruning operation). This leads to the identification of a compact textural signature characterizing lesion phenotype. On the patch-level task of acute versus chronic MS lesion classification, our method achieves a balanced accuracy in the range of 74.3-74.6% on fully external validation cohorts.

061 Ocrelizumab reduces disability progression independent of relapse activity in patients with relapsing multiple sclerosis (RMS) (ENCORE)

Introduction

Ocrelizumab-(OCR) showed superior efficacy vs interferon beta-1a-(IFNβ1a) in OPERA I/II trials in RMS. Confirmed disability progression-(CDP) based on composite of Expanded Disability Status Scale-(EDSS), timed 25-foot walk-(T25FW) and 9-hole peg test-(9HPT) may better characterise aspects of disability progression than EDSS alone and has improved sensitivity for assessing progression in secondary progressive MS-(SPMS).

Methods

RMS patients, including relapsing SPMS patients, in OPERA I/II-(NCT01247324/NCT01412333) received IV-OCR 600 mg (q24w) or SC-IFNβ1a 44 µg (tiw) over 96 weeks. CCDP was defined as disability progression measured by EDSS (increase ≥1.0 or 0.5 if baseline >5.5) or ≥20% T25FW increase or ≥20% 9 HPT increase, confirmed after ≥12/≥24 weeks. Definition-1 of CCDP-IRA=reference EDSS/T25FW/9HPT was re-baselined at first available assessment ≥30 days, after each relapse and no relapse should occur between baseline and initial disability progression [IDP], and within 30 days post-IDP and 30 days prior to IDP confirmation. Definition-2=period of no relapse for 30 days post-IDP confirmation. Subgroup analysis included patients at potentially higher SPMS risk based on baseline-EDSS ≥4.0 and pyramidal Kurtzke Functional Systems Score ≥2.

Results

In the pooled intention-to-treat (ITT) cohort (n=1,656), risk reduction (RR; OCR vs IFNβ1a) for 12-/24 week CCDP was 34% (30.7% vs 21.5%; p<0.001) and 31% (22.6% vs 16.1%; p=0.002). The 12-/24 week CCDP-IRA RRs for Definition-1 were 24% (25.4% vs 19.6%; p=0.010) and 22% (19.2% vs 14.9%; p=0.046); and for Definition-2, 25% (25.4% vs 19.5%; p=0.008) and 23% (19.2% vs 14.8%; p=0.039). In the subgroup at higher SPMS risk, 12-/24 week RRs for CCDP-IRA (Definition-2) were 40% (31.2% vs 19.1%; p=0.022) and 36% (26.9% vs 16.6%; p=0.064). All CCDP-IRA components in the ITT and subgroups followed similar trends.

Conclusion

Results show that considerable disability progression in RMS occurs independently of protocol-defined relapses. Ocrelizumab significantly reduced progression vs IFNβ1a in the OPERA ITT population of RMS patients and more so in the subgroup at higher SPMS risk.

Chromosomal ampC mutations in cefpodoxime-resistant, ESBL-negative uropathogenic Escherichia coli

AmpC β-lactamase is an enzyme commonly produced by Escherichia coli that causes resistance to cephalosporins and penicillins. Enzyme production is controlled by the strength of the promoter encoded by the chromosomal ampC gene, with the level of production affected by the presence of certain mutations in this region. This study sets out to determine the prevalence of ampC promoter mutations present in a group of uropathogenic E. coli strains. A total of 50 clinical strains of E. coli were collected from urine samples between June 2011 and November 2011. Strains were investigated for the presence of mutations in the chromosomal ampC promoter region by amplification and sequencing of a 271 bp product. The presence of ampC-carrying plasmids derived from other species was also determined, to exclude these from further analysis. ampC-carrying plasmids were found in 10 of the 50 strains, all of which were of the CIT-type. Analysis of the chromosomal ampC promoter region in the 40 remaining strains showed mutations at 16 different positions, with 18 different genotype patterns detected overall. The most common ampC chromosomal mutation, present in 25 of 40 strains, was a T --> A transition at position -32. This mutation has been shown by others to increase enzyme production by up to 46-fold. Altogether, three separate mutations (-32, -42 and -13ins) were present in 90% of the 40 non-plasmid strains, indicating a strong association with the resistance observed. It appears, therefore, that the majority of AmpC-mediated resistance in E. coli can be accounted for by just three point mutations in the chromosome.

Trial designs likely to meet valid long-term Alzheimer's disease progression effects: learning from the past, preparing for the future

The International Society for CNS Clinical Trials and Methodology (ISCTM) held its 4th Annual Autumn Conference in Toronto, Ontario, October 6-7, 2008. The purpose of the present report is to provide an overview of one of the sessions at the conference which focused on the designs and methodologies to be applied in clinical trials of new treatments for Alzheimer's disease (AD) with purported “disease-modifying” effects. The session began with a discussion of how neuroimaging has been applied in multiple sclerosis clinical trials (another condition for which disease modification claims have been achieved). The next two lectures provided a pharmaceutical industry perspective on some of the specific challenges and possible solutions for designing trials to measure disease progression and/or modification. The final lecture provided an academic viewpoint and the closing discussion included additional academic and regulatory perspectives on trial designs, methodologies, and statistical issues relevant to the disease modification concept.