Publications by authors named "Andrea Andrade"

39 Publications

Pediatric Hyperacute Arterial Ischemic Stroke Pathways at Canadian Tertiary Care Hospitals.

Can J Neurol Sci 2021 Feb 11:1-8. Epub 2021 Feb 11.

University of Ottawa, Faculty of Medicine, Ottawa, ON, Canada.

Background: Childhood acute arterial ischemic stroke (AIS) is diagnosed at a median of 23 hours post-symptom onset, delaying treatment. Pediatric stroke pathways can expedite diagnosis. Our goal was to understand the similarities and differences between Canadian pediatric stroke protocols with the aim of optimizing AIS management.

Methods: We contacted neurologists at all 16 Canadian pediatric hospitals regarding AIS management. Established protocols were analyzed for similarities and differences in eight domains.

Results: Response rate was 100%. Seven (44%) centers have an established AIS protocol and two (13%) have a protocol under development. Seven centers do not have a protocol; two redirect patients to adult neurology, five rely on a case-by-case approach for management. Analysis of the seven protocols revealed differences in: 1) IV-tPA dosage: age-dependent 0.75-0.9 mg/kg (N = 1) versus age-independent 0.9 mg/kg (N = 6), with maximum doses of 75 mg (N = 1) or 90 mg (N = 6); 2) IV-tPA lower age cut-off: 2 years (N = 5) versus 3 or 10 years (each N = 1); 3) IV-tPA exclusion criteria: PedNIHSS score <4 (N = 3), <5 (N = 1), <6 (N = 3); 4) first choice of pre-treatment neuroimaging: computed tomography (CT) (N = 3), magnetic resonance imaging (MRI) (N = 2) or either (N = 2); 5) intra-arterial tPA use (N = 3) and; 6) mechanical thrombectomy timeframe: <6 hour (N = 3), <24 hour (N = 2), unspecified (N = 2).

Conclusions: Although 44% of Canadian pediatric hospitals have established AIS management pathways, several differences remain among centers. Some criteria (dosage, imaging) reflect adult AIS literature. Canadian expert consensus regarding IV-tPA and endovascular treatment should be established to standardize and implement AIS protocols across Canada.
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http://dx.doi.org/10.1017/cjn.2021.27DOI Listing
February 2021

Presurgical brain mapping of the language network in pediatric patients with epilepsy using resting-state fMRI.

J Neurosurg Pediatr 2021 Jan 8:1-10. Epub 2021 Jan 8.

6Clinical Neurological Sciences, London Health Sciences Centre, University of Western Ontario, London, Ontario, Canada.

Objective: Epilepsy affects neural processing and often causes intra- or interhemispheric language reorganization, rendering localization solely based on anatomical landmarks (e.g., Broca's area) unreliable. Preoperative brain mapping is necessary to weigh the risk of resection with the risk of postoperative deficit. However, the use of conventional mapping methods (e.g., somatosensory stimulation, task-based functional MRI [fMRI]) in pediatric patients is technically difficult due to low compliance and their unique neurophysiology. Resting-state fMRI (rs-fMRI), a "task-free" technique based on the neural activity of the brain at rest, has the potential to overcome these limitations. The authors hypothesized that language networks can be identified from rs-fMRI by applying functional connectivity analyses.

Methods: Cases in which both task-based fMRI and rs-fMRI were acquired as part of the preoperative clinical protocol for epilepsy surgery were reviewed. Task-based fMRI consisted of 2 language tasks and 1 motor task. Resting-state fMRI data were acquired while the patients watched an animated movie and were analyzed using independent component analysis (i.e., data-driven method). The authors extracted language networks from rs-fMRI data by performing a similarity analysis with functionally defined language network templates via a template-matching procedure. The Dice coefficient was used to quantify the overlap.

Results: Thirteen children underwent conventional task-based fMRI (e.g., verb generation, object naming), rs-fMRI, and structural imaging at 1.5T. The language components with the highest overlap with the language templates were identified for each patient. Language lateralization results from task-based fMRI and rs-fMRI mapping were comparable, with good concordance in most cases. Resting-state fMRI-derived language maps indicated that language was on the left in 4 patients (31%), on the right in 5 patients (38%), and bilateral in 4 patients (31%). In some cases, rs-fMRI indicated a more extensive language representation.

Conclusions: Resting-state fMRI-derived language network data were identified at the patient level using a template-matching method. More than half of the patients in this study presented with atypical language lateralization, emphasizing the need for mapping. Overall, these data suggest that this technique may be used to preoperatively identify language networks in pediatric patients. It may also optimize presurgical planning of electrode placement and thereby guide the surgeon's approach to the epileptogenic zone.
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http://dx.doi.org/10.3171/2020.8.PEDS20517DOI Listing
January 2021

Longitudinal changes in emotional functioning following pediatric resective epilepsy surgery: 2-Year follow-up.

Epilepsy Behav 2021 01 1;114(Pt A):107585. Epub 2020 Dec 1.

Neurosciences and Mental Health Program, The Hospital for Sick Children, Toronto, ON, Canada; Department of Psychology, The Hospital for Sick Children, Toronto, ON, Canada; Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada. Electronic address:

Objective: To examine longitudinal changes and predictors of depression and anxiety 2 years following resective epilepsy surgery, compared to no surgery, in children with drug-resistant epilepsy (DRE).

Method: This multicenter cohort study involved 128 children and adolescents with DRE (48 surgical, 80 nonsurgical; 8-18 years) who completed self-report measures of depression and anxiety at baseline and follow-up (6-month, 1-year, 2-year). Child demographic (age, sex, IQ) and seizure (age at onset, duration, frequency, site and side) variables were collected.

Results: Linear mixed-effects models controlling for age at enrolment found a time by treatment by seizure outcome interaction for depression. A negative linear trend across time (reduction in symptoms) was found for surgical patients, irrespective of seizure outcome. In contrast, the linear trend differed depending on seizure outcome in nonsurgical patients; a negative trend was found for those with continued seizures, whereas a positive trend (increase in symptoms) was found for those who achieved seizure freedom. Only a main effect of time was found for anxiety indicating a reduction in symptoms across patient groups. Multivariate regressions failed to find baseline predictors of depression or anxiety at 2-year follow-up in surgical patients. Older age, not baseline anxiety or depression, predicted greater symptoms of anxiety and depression at 2-year follow-up in nonsurgical patients.

Conclusion: Children with DRE reported improvement in anxiety and depression, irrespective of whether they achieve seizure control, across the 2 years following surgery. In contrast, children with DRE who did not undergo surgery, but achieved seizure freedom, reported worsening of depressive symptoms, which may indicate difficulty adjusting to life without seizures and highlight the potential need for ongoing medical and psychosocial follow-up and support.
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http://dx.doi.org/10.1016/j.yebeh.2020.107585DOI Listing
January 2021

A live-online mindfulness-based intervention for children living with epilepsy and their families: protocol for a randomized controlled trial of Making Mindfulness Matter©.

Trials 2020 Nov 11;21(1):922. Epub 2020 Nov 11.

Department of Epidemiology & Biostatistics, Western University, Kresge Building, Room K201, 1151 Richmond Street, London, ON, N6A 5C1, Canada.

Background: Epilepsy extends far beyond seizures; up to 80% of children with epilepsy (CWE) may have comorbid cognitive or mental health problems, and up to 50% of parents of CWE are at risk for major depression. Past research has also shown that family environment has a greater influence on children's and parents' health-related quality of life (HRQOL) and mental health than epilepsy-related factors. There is a pressing need for low-cost, innovative interventions to improve HRQOL and mental health for CWE and their parents. The aim of this randomized controlled trial (RCT) is to evaluate whether an interactive online mindfulness-based intervention program, Making Mindfulness Matter (M3), can be feasibly implemented and whether it positively affects CWE's and parents' HRQOL and mental health (specifically, stress, behavioral, depressive, and anxiety symptoms).

Methods: This parallel RCT was planned to recruit 100 child-parent dyads to be randomized 1:1 to the 8-week intervention or waitlist control and followed over 20 weeks. The intervention, M3, will be delivered online and separately to parents and children (ages 4-10 years) in groups of 4-8 by non-clinician staff of a local community epilepsy agency. The intervention incorporates mindful awareness, social-emotional learning skills, and positive psychology. It is modeled after the validated school-based MindUP program and adapted for provision online and to include a parent component.

Discussion: This RCT will determine whether this online mindfulness-based intervention is feasible and effective for CWE and their parents. The proposed intervention may be an ideal vector to significantly improve HRQOL and mental health for CWE and their parents given its low cost and implementation by community epilepsy agencies.

Trial Registration: ClinicalTrials.gov NCT04020484 . Registered on July 16, 2019.
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http://dx.doi.org/10.1186/s13063-020-04792-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7657360PMC
November 2020

Teaching NeuroImages: Reversible neuroimaging findings during treatment of infantile spasms with vigabatrin.

Neurology 2020 10 16;95(16):e2314-e2315. Epub 2020 Jul 16.

From the Department of Clinical Neurological Sciences (D.D.K., A.K.S.), Division of Neuroradiology, Department of Radiology (M.S.), and Division of Pediatric Neurology, Department of Pediatrics (A.A.), Western University, London, Canada.

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http://dx.doi.org/10.1212/WNL.0000000000010370DOI Listing
October 2020

Vagus nerve stimulation in patients with therapy-resistant generalized epilepsy.

Epilepsy Behav 2020 10 29;111:107253. Epub 2020 Jun 29.

Epilepsy Program, Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada; Neuroepidemiology Unit, Schulich School of Medicine, Western University, London, ON, Canada.

Background: For patients with generalized epilepsy who do not respond to antiseizure medications, the therapeutic options are limited. Vagus nerve stimulation (VNS) is a treatment mainly approved for therapy-resistant focal epilepsy. There is limited information on the use of VNS on generalized epilepsies, including Lennox-Gastaut Syndrome (LGS) and genetic generalized epilepsy (GGE).

Methods: We identified patients with a diagnosis of generalized epilepsy (including LGS and GGE), who underwent VNS implantation at the London Health Sciences Centre and Western University, London, Ontario, since this treatment became available in Canada in 1997 until July 2018. We assessed response to the treatment, including admissions to hospital and complications.

Results: A total of 46 patients were included in this study with a history of therapy-resistant generalized epilepsy. The mean age at implantation was 24 years (interquartile range [IQR] = 17.8-31 years), significantly younger in the LGS group (p = 0.02) and 50% (n = 23) were female. The most common etiologies were GGE in 37% (n = 17) and LGS in 63% (n = 29). Median follow-up since VNS implantation was 63 months (IQR: 31-112.8 months). Of the LGS group 41.7% (n = 12) of patients had an overall seizure reduction of 50% or more, and 64.7% (n = 11) in the GGE group without statistical significance between the groups. The best response in seizure reduction was seen in generalized tonic-clonic seizures, with a significant reduction in the GGE group (p = 0.043). There was a reduction of seizure-related hospital admissions from 91.3% (N = 42) preimplantation, to 43.5% (N = 20) postimplantation (p < 0.05). The frequency of side effects due to the stimulation was almost equal in both groups (62.1% in LGS and 64.7% in GGE).

Conclusions: Vagus nerve stimulation should be considered as a treatment in patients with therapy-resistant generalized epilepsy, especially in cases with GGE.
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http://dx.doi.org/10.1016/j.yebeh.2020.107253DOI Listing
October 2020

Biochemical and molecular approach of oxidative damage triggered by water stress and rewatering in sunflower seedlings of two inbred lines with different ability to tolerate water stress.

Funct Plant Biol 2020 07;47(8):727-743

Laboratorio de Fisiología Vegetal, Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, UNRC, Instituto de Investigaciones Agrobiotecnológicas-Consejo Nacional de Investigaciones Científicas y Técnicas (INIAB-CONICET), 5800-Río Cuarto, Córdoba, Argentina; and Corresponding author. Email:

Water stress accelerates the generation of reactive oxygen species, which trigger a cascade of antioxidative defence mechanisms comprising enzymatic and nonenzymatic antioxidants. The aim of this study was to investigate the oxidative damage and the antioxidative defence systems in seedlings of the water stress-tolerant (B71) and the sensitive (B59) inbred lines of sunflower (Helianthus annuus L.) in response to water stress and rewatering. In addition, we characterised the transcriptomic profile associated with enzymatic antioxidative defence. An elevated electrolyte leakage in B59 indicated increased plasmatic membrane permeability, which correlated with greater sensitivity to water stress. In response to water stress, both lines showed an increase in malondialdehyde and H2O2 content but these increases were more noticeable in the sensitive line. In both lines, an increase in enzymatic activity (e.g. peroxidase and ascorbate peroxidase) was not sufficient to overcome the H2O2 accumulation triggered by water stress. Upon water stress, the overall expression level of genes associated with the enzymatic antioxidant system increased in B71 and decreased in B59, which showed downregulated levels of most genes in the shoots. The general profile of phenolic compounds was clearly different between organs and between inbred lines. The B59 line activated nonenzymatic antioxidant responses to counteract the oxidative stress caused by water stress. The tolerance of B71 to water stress could be associated with compensatory antioxidant mechanisms based on the expression of genes encoding enzyme components of the ascorbate-glutathione and redoxin cycles, which contributed to explaining, at least partly, the response of this line.
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http://dx.doi.org/10.1071/FP19264DOI Listing
July 2020

Interventions for chronic pruritus of unknown origin.

Cochrane Database Syst Rev 2020 01 25;1:CD013128. Epub 2020 Jan 25.

Instituto Universitario Hospital Italiano, Argentine Cochrane Centre, Potosi 4234, Buenos Aires, Buenos Aires, Argentina, C1199ACL.

Background: Pruritus is a sensation that leads to the desire to scratch; its origin is unknown in 8% to 15% of affected patients. The prevalence of chronic pruritus of unknown origin (CPUO) in individuals with generalised pruritus ranges from 3.6% to 44.5%, with highest prevalence among the elderly. When the origin of pruritus is known, its management may be straightforward if an effective treatment for the causal disease is available. Treatment of CPUO is particularly difficult due to its unknown pathophysiology.

Objectives: To assess the effects of interventions for CPUO in adults and children.

Search Methods: We searched the following up to July 2019: Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and trials registries. We checked the reference lists of included studies for additional references to relevant trials.

Selection Criteria: We sought to include randomised controlled trials and quasi-randomised controlled trials that assessed interventions for CPUO, as defined in category VI ('Other pruritus of undetermined origin, or chronic pruritus of unknown origin') of the International Forum for the Study of Itch (IFSI) classification, in children and adults. Eligible interventions were non-pharmacological or topical or systemic pharmacological interventions, and eligible comparators were another active treatment, placebo, sham procedures, or no treatment or equivalent (e.g. waiting list).

Data Collection And Analysis: We used standard methodological procedures expected by Cochrane. Our primary outcomes were 'Patient- or parent-reported pruritus intensity' and 'Adverse events'. Our secondary outcomes were 'Health-related quality of life', 'Sleep disturbances', 'Depression', and 'Patient satisfaction'. We used GRADE to assess the certainty of evidence.

Main Results: We found there was an absence of evidence for the main interventions of interest: emollient creams, cooling lotions, topical corticosteroids, topical antidepressants, systemic antihistamines, systemic antidepressants, systemic anticonvulsants, and phototherapy. We included one study with 257 randomised (253 analysed) participants, aged 18 to 65 years; 60.6% were female. This study investigated the safety and efficacy of three different doses of oral serlopitant (5 mg, 1 mg, and 0.25 mg, once daily for six weeks) compared to placebo for severe chronic pruritus; 25 US centres participated (clinical research centres and universities). All outcomes were measured at the end of treatment (six weeks from baseline), except adverse events, which were monitored throughout. A pharmaceutical company funded this study. Fifty-five per cent of participants suffered from CPUO, and approximately 45% presented a dermatological diagnosis (atopic dermatitis/eczema 37.3%, psoriasis 6.7%, acne 3.6%, among other diagnoses). We unsuccessfully attempted to retrieve outcome data from study authors for the subgroup of participants with CPUO. Participants had pruritus for six weeks or longer. Total study duration was 10 weeks. Participants who received serlopitant 5 mg may have a greater rate of relief of patient-reported pruritus intensity as measured by the visual analogue scale (VAS; a reduction in VAS score indicates improvement) compared to placebo (126 participants, risk ratio (RR) 2.06, 95% confidence interval (CI) 1.27 to 3.35; low-certainty evidence). We are uncertain of the effects of serlopitant 5 mg compared to placebo on the following outcomes due to very low-certainty evidence: adverse events (127 participants; RR 1.48, 95% CI 0.87 to 2.50); health-related quality of life (as measured by the Dermatology Life Quality Index (DLQI); a higher score indicates greater impairment; 127 participants; mean difference (MD) -4.20, 95% CI -11.68 to 3.28); and sleep disturbances (people with insomnia measured by the Pittsburgh Sleep Symptom Questionnaire-Insomnia (PSSQ-I), a dichotomous measure; 128 participants; RR 0.49, 95% CI 0.24 to 1.01). Participants who received serlopitant 1 mg may have a greater rate of relief of patient-reported pruritus intensity as measured by VAS compared to placebo; however, the 95% CI indicates that there may also be little to no difference between groups (126 participants; RR 1.50, 95% CI 0.89 to 2.54; low-certainty evidence). We are uncertain of the effects of serlopitant 1 mg compared to placebo on the following outcomes due to very low-certainty evidence: adverse events (128 participants; RR 1.45, 95% CI 0.86 to 2.47); health-related quality of life (DLQI; 128 participants; MD -6.90, 95% CI -14.38 to 0.58); and sleep disturbances (PSSQ-I; 128 participants; RR 0.38, 95% CI 0.17 to 0.84). Participants who received serlopitant 0.25 mg may have a greater rate of relief of patient-reported pruritus intensity as measured by VAS compared to placebo; however, the 95% CI indicates that there may also be little to no difference between groups (127 participants; RR 1.66, 95% CI 1.00 to 2.77; low-certainty evidence). We are uncertain of the effects of serlopitant 0.25 mg compared to placebo on the following outcomes due to very low-certainty evidence: adverse events (127 participants; RR 1.29, 95% CI 0.75 to 2.24); health-related quality of life (DLQI; 127 participants; MD -5.70, 95% CI -13.18 to 1.78); and sleep disturbances (PSSQ-I; 127 participants; RR 0.60, 95% CI 0.31 to 1.17). The most commonly reported adverse events were somnolence, diarrhoea, headache, and nasopharyngitis, among others. Our included study did not measure depression or patient satisfaction. We downgraded the certainty of evidence for all outcomes due to indirectness (only 55% of study participants had CPUO) and imprecision. We downgraded outcomes other than patient-reported pruritus intensity a further level due to concerns regarding risk of bias in selection of the reported result and some concerns with risk of bias due to missing outcome data (sleep disturbances only). We deemed risk of bias to be generally low.

Authors' Conclusions: We found lack of evidence to address our review question: for most of our interventions of interest, we found no eligible studies. The neurokinin 1 receptor (NK1R) antagonist serlopitant was the only intervention that we could assess. One study provided low-certainty evidence suggesting that serlopitant may reduce pruritus intensity when compared with placebo. We are uncertain of the effects of serlopitant on other outcomes, as certainty of the evidence is very low. More studies with larger sample sizes, focused on patients with CPUO, are needed. Healthcare professionals, patients, and other stakeholders may have to rely on indirect evidence related to other forms of chronic pruritus when deciding between the main interventions currently used for this condition.
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http://dx.doi.org/10.1002/14651858.CD013128.pub2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6984650PMC
January 2020

Seizure freedom improves health-related quality of life after epilepsy surgery in children.

Dev Med Child Neurol 2020 05 11;62(5):600-608. Epub 2019 Nov 11.

Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.

Aim: To determine whether epilepsy surgery improved health-related quality of life (HRQoL) and whether seizure freedom after surgery mediated the improvement in HRQoL.

Method: This multicenter cohort study compared HRQoL after epilepsy surgery to pharmacological management in children with drug-resistant epilepsy (DRE). HRQoL was measured using the Quality of Life in Childhood Epilepsy (QOLCE) questionnaire at baseline and 1-year follow-up. The mediator between treatment type and HRQoL was seizure freedom.

Results: Two hundred and thirty-seven patients were recruited (surgery group: n=147 [92 males, 45 females]; pharmacological group: n=90 [53 males, 37 females]). Mean age at seizure onset was 6 years (SD 4y 4mo) in the surgical group and 6 years 1 month (SD 4y) in the pharmacological group. The odds ratio of seizure freedom was higher for the surgery versus pharmacological group (β=4.24 [95% confidence interval {CI}: 2.26-7.93], p<0.001). Surgery had no direct effect on total QOLCE score at 1-year (β=0.24 [95% CI -2.04 to 2.51], p=0.839) compared to pharmacological management, but had an indirect effect on total QOLCE that was mediated by seizure freedom (β=0.92 [95% CI 0.19-1.65], p=0.013), adjusting for baseline total QOLCE score. Surgery had a direct effect on improving social function (p=0.043), and an indirect effect on improving physical function (p=0.016), cognition (p=0.042), social function (p=0.012) and behavior (p=0.032), mediated by seizure freedom.

Interpretation: Greater seizure freedom achieved through epilepsy surgery mediated the improvement in HRQoL compared to pharmacological management in children with DRE.

What This Paper Adds: Seizure freedom is higher after pediatric epilepsy surgery compared to pharmacologically managed epilepsy. Surgery indirectly improves health-related quality of life (HRQoL) mediated by seizure freedom compared to pharmacological management. Surgery has a direct effect on improving social function relative to pharmacological management. Baseline HRQoL was an important predictor of HRQoL after treatment.
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http://dx.doi.org/10.1111/dmcn.14390DOI Listing
May 2020

Spatiotemporal variations in salicylic acid and hydrogen peroxide in sunflower seeds during transition from dormancy to germination.

Physiol Plant 2020 May 27;169(1):27-39. Epub 2019 Nov 27.

Laboratorio de Fisiología Vegetal, Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, UNRC, INIAB-CONICET, Rio Cuarto, Argentina.

Phytohormones and reactive oxygen species mediate processes such as germination and dormancy. The elucidation of the physiological and biochemical events implicated in the transition from dormancy to germination in different plant species such as sunflower becomes a topic of interest. In this study, we investigated the spatiotemporal variation of salicylic acid (SA), hydrogen peroxide (H O ) and the activity of two antioxidant enzymes (catalase, CAT - EC 1.11.1.6 and ascorbate peroxidase - EC 1.11.1.11) in embryonic axis and cotyledons of dry and imbibed seeds of dormant (B123) and non-dormant (B91) sunflower lines. The results showed that embryonic axis had higher level of SA and H O than cotyledons in both lines. In dry seeds, B123 embryo (embryonic axis + cotyledons) showed a higher SA content than B91. After dry storage at room temperature, SA decreased in B123 embryos to a value close to that registered in B91 embryos. B123 embryonic axis of dry seeds presented higher H O levels than B91. Dry storage led to an increase of H O levels and a decrease of CAT activity in B123 embryonic axis. During imbibition, B123 seeds stored for 33 days displayed an increase in SA level in the embryonic axis (3 h of imbibition) and this lower level correlated with a decrease in H O (6 h of imbibition). Thus, the embryo-imposed dormancy in B123 dry seeds was associated with high levels of SA and low H O , whereas the dormancy release was linked with SA decrease and increase of H O as a consequence of lower CAT activity.
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http://dx.doi.org/10.1111/ppl.13043DOI Listing
May 2020

Linkage disequilibrium and haplotype block patterns in popcorn populations.

PLoS One 2019 25;14(9):e0219417. Epub 2019 Sep 25.

Federal University of Viçosa, Department of Animal Science, Viçosa, MG, Brazil.

Linkage disequilibrium (LD) analysis provides information on the evolutionary aspects of populations. Recently, haplotype blocks have been used to increase the power of quantitative trait loci detection in genome-wide association studies and the prediction accuracy of genomic selection. Our objectives were as follows: to compare the degree of LD, LD decay, and LD decay extent in popcorn populations; to characterize the number and length of haplotype blocks in the populations; and to determine whether maize chromosomes also have a pattern of interspaced regions of high and low rates of recombination. We used a biparental population, a synthetic, and a breeding population, genotyped for approximately 75,000 single nucleotide polymorphisms (SNPs). The sample size ranged from 190 to 192 plants. For the whole-genome LD and haplotype block analyses, we assumed a window of 500 kb. To characterize the block and step patterns of LD in the populations, we constructed LD maps by chromosome, defining a cold spot as a chromosome segment including SNPs with the same LDU position. The LD and haplotype block analyses were also performed at the intragenic level, selecting 12 genes related to zein, starch, cellulose, and fatty acid biosynthesis. The populations with the higher and lower frequencies of |D'| values greater than 0.75 were the biparental (65-74%) and the breeding population (26-58%), respectively. There were slight differences between the populations regarding the average distance for SNPs with |D'| values greater than 0.75 (in the range of approximately 207 to 229 kb). The level of LD expressed by the r2 values was low in the populations (0.02, 0.04, and 0.04, on average) but comparable to some non-isolated human populations. The frequency of r2 values greater than 0.75 was lower in the biparental population (0.2-0.5%) and higher in the other populations (0.2-1.6%). The average distance for SNPs with r2 values greater than 0.75 was much higher in the biparental population (approximately 80 to 126 kb). In the other populations, the ranges were approximately 6 to 19 and 6 to 35 kb. The heatmaps for the regions covered by the first 100 SNPs in each chromosome, in each population (1 to 3.3 Mb, approximately), provided evidence that the comparatively few high r2 values (close to 1.0) occurred only for SNPs in close proximity, especially in the synthetic and breeding populations. Due to the reduced number of SNPs in the haplotype blocks (2 to 3) in the populations, it is not expected advantage of a haplotype-based association study as well as genomic selection along generations. The results concerning LD decay (rapid decay after 5-10 kb) and LD decay extent (along up to 300 kb) are in the range observed with maize inbred line panels. The LD maps indicate that maize chromosomes had a pattern of regions of extensive LD interspaced with regions of low LD. However, our simulated LD map provides evidence that this pattern can reflect regions with differences in allele frequencies and LD levels (expressed by |D'|) and not regions with high and low rates of recombination.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0219417PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6760792PMC
March 2020

Infantile-Onset Multisystem Neurologic, Endocrine, and Pancreatic Disease: Case and Review.

Can J Neurol Sci 2019 07 6;46(4):459-463. Epub 2019 May 6.

Department of Pediatrics, London, Ontario,Canada.

We report three brothers born to consanguineous parents of Syrian descent, with a homozygous novel c.324G>A (p.W108*) mutation in PTRH2 that encodes peptidyl-tRNA hydrolase 2, causing infantile-onset multisystem neurologic, endocrine, and pancreatic disease (IMNEPD). We describe the core clinical features of postnatal microcephaly, motor and language delay with regression, ataxia, and hearing loss. Additional features include epileptic seizures, pancreatic insufficiency, and peripheral neuropathy. Clinical phenotyping enabled a targeted approach to the investigation and identification of a novel homozygous nonsense mutation in PTRH2, c.324G>A (p.W108*). We compare our patients with those recently described and review the current literature for IMNEPD.
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http://dx.doi.org/10.1017/cjn.2019.35DOI Listing
July 2019

The mitochondrial oxidation resistance protein AtOXR2 increases plant biomass and tolerance to oxidative stress.

J Exp Bot 2019 06;70(12):3177-3195

Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.

This study demonstrates the existence of the oxidation resistance (OXR) protein family in plants. There are six OXR members in Arabidopsis that contain the highly conserved TLDc domain that is characteristic of this eukaryotic protein family. AtOXR2 is a mitochondrial protein able to alleviate the stress sensitivity of a yeast oxr1 mutant. It was induced by oxidative stress and its overexpression in Arabidopsis (oeOXR2) increased leaf ascorbate, photosynthesis, biomass, and seed production, as well as conferring tolerance to methyl viologen, antimycin A, and high light intensities. The oeOXR2 plants also showed higher ABA content, changes in ABA sensitivity, and modified expression of ABA- and stress-regulated genes. While the oxr2 mutants had a similar shoot phenotype to the wild-type, they exhibited increased sensitivity to stress. We propose that by influencing the levels of reactive oxygen species (ROS), AtOXR2 improves the efficiency of photosynthesis and elicits basal tolerance to environmental challenges that increase oxidative stress, allowing improved plant growth and biomass production.
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http://dx.doi.org/10.1093/jxb/erz147DOI Listing
June 2019

Anatomical Venous Variants in Children With Cerebral Sinovenous Thrombosis.

Stroke 2018 Dec 3:STROKEAHA118023482. Epub 2018 Dec 3.

From the Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada (E.K., D.L.M., G.d., N.D., M.M.).

Background and Purpose- Literature is sparse on the frequency and significance of anatomical venous variants (AVVs) in pediatric cerebral sinovenous thrombosis (CSVT). Methods- We retrospectively reviewed children with CSVT and controls undergoing computed tomography/magnetic resonance venography from January 2008 to 2014. Clinical features examined included raised intracranial pressure, risk factors, and treatment. Radiological features examined included CSVT location, presence and type of AVVs, hemorrhagic venous infarction, and venous collateralization. Clinical outcome was measured by the pediatric stroke outcome measure and radiological outcome by thrombus recanalization. Results- Fifty-one children with CSVT were identified. Twenty-two (43%) had AVVs at presentation. Nineteen (86%) had hypoplasia/absence of major dural sinus, 5 (23%) had persistent fetal structures, 3 (14%) had duplications/fenestrations, and 1 (5%) had disconnected superficial and deep venous systems. Controls had a slightly higher but nonsignificant prevalence 26 (51%) of AVVs. No significant clinical and radiological differences were observed between children with CSVT and AVVs compared with those with typical venous anatomy. Conclusions- AVVs are seen in many children with and without CSVT and do not seem to alter the presentation or clinical course. The influence of these variations on the brain's ability to tolerate venous congestion because of thrombosis merits further study.
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http://dx.doi.org/10.1161/STROKEAHA.118.023482DOI Listing
December 2018

Long-Day Photoperiod Enhances Jasmonic Acid-Related Plant Defense.

Plant Physiol 2018 09 1;178(1):163-173. Epub 2018 Aug 1.

Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura, Facultad de Agronomía, C1417DSE Buenos Aires, Argentina

Agricultural crops are exposed to a range of daylengths, which act as important environmental cues for the control of developmental processes such as flowering. To explore the additional effects of daylength on plant function, we investigated the transcriptome of Arabidopsis () plants grown under short days (SD) and transferred to long days (LD). Compared with that under SD, the LD transcriptome was enriched in genes involved in jasmonic acid-dependent systemic resistance. Many of these genes exhibited impaired expression induction under LD in the (), (), and triple photoreceptor mutant. Compared with that under SD, LD enhanced plant resistance to the necrotrophic fungus This response was reduced in the triple mutant, in the () mutant, in the mutant, and in mutants impaired in DELLA function. Plants grown under SD had an increased nuclear abundance of COP1 and decreased DELLA abundance, the latter of which was dependent on COP1. We conclude that growth under LD enhances plant defense by reducing COP1 activity and enhancing DELLA abundance and expression.
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http://dx.doi.org/10.1104/pp.18.00443DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6130044PMC
September 2018

Psychosocial risks at the workplace and quality of life in cancer survivors in employment.

Psychooncology 2018 04 8;27(4):1347-1349. Epub 2018 Feb 8.

Center for Health Technology and Services Research (CINTESIS), Department of Education and Psychology, University of Aveiro, Aveiro, Portugal.

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http://dx.doi.org/10.1002/pon.4644DOI Listing
April 2018

Relevance of genetic relationship in GWAS and genomic prediction.

J Appl Genet 2018 Feb 30;59(1):1-8. Epub 2017 Nov 30.

Department of General Biology, Federal University of Viçosa, Viçosa, MG, 36570-900, Brazil.

The objective of this study was to analyze the relevance of relationship information on the identification of low heritability quantitative trait loci (QTLs) from a genome-wide association study (GWAS) and on the genomic prediction of complex traits in human, animal and cross-pollinating populations. The simulation-based data sets included 50 samples of 1000 individuals of seven populations derived from a common population with linkage disequilibrium. The populations had non-inbred and inbred progeny structure (50 to 200) with varying number of members (5 to 20). The individuals were genotyped for 10,000 single nucleotide polymorphisms (SNPs) and phenotyped for a quantitative trait controlled by 10 QTLs and 90 minor genes showing dominance. The SNP density was 0.1 cM and the narrow sense heritability was 25%. The QTL heritabilities ranged from 1.1 to 2.9%. We applied mixed model approaches for both GWAS and genomic prediction using pedigree-based and genomic relationship matrices. For GWAS, the observed false discovery rate was kept below the significance level of 5%, the power of detection for the low heritability QTLs ranged from 14 to 50%, and the average bias between significant SNPs and a QTL ranged from less than 0.01 to 0.23 cM. The QTL detection power was consistently higher using genomic relationship matrix. Regardless of population and training set size, genomic prediction provided higher prediction accuracy of complex trait when compared to pedigree-based prediction. The accuracy of genomic prediction when there is relatedness between individuals in the training set and the reference population is much higher than the value for unrelated individuals.
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http://dx.doi.org/10.1007/s13353-017-0417-2DOI Listing
February 2018

A 7-month-old with 'loss of muscle control'.

Emerg Med J 2017 Aug;34(8):555

Departments of Paediatrics and Medicine, Schulich School of Medicine at the University of Western Ontario, Children's Hospital at London Health Sciences Centre, London, Ontario, Canada.

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http://dx.doi.org/10.1136/emermed-2016-206201DOI Listing
August 2017

A pediatric institutional acute stroke protocol improves timely access to stroke treatment.

Dev Med Child Neurol 2017 01 4;59(1):31-37. Epub 2016 Aug 4.

Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada.

Aim: We aimed to evaluate whether an institutional acute stroke protocol (ASP) could accelerate the diagnosis and secondary treatment of pediatric stroke.

Method: We initiated an ASP in 2005. We compared 209 children (125 males, 84 females; median age 4.8y, interquartile range [IQR] 1.2-9.3y, range 0.09-17.7y) diagnosed with arterial ischemic stroke 'pre-protocol' (1992-2004) to 112 children (60 males, 52 females; median age 5.8y, IQR 1.0-11.4y, range 0.08-17.7y) diagnosed 'post-protocol' (2005-2012) for time-to-diagnosis, mode of diagnostic imaging, and time-to-treatment with antithrombotic medication (aspirin or anticoagulants).

Results: Overall, the interval from symptom onset to diagnosis was similar post-protocol compared to pre-protocol (20.3 vs 22.7h; p=0.109), although mild strokes (Pediatric National Institute of Health Stroke Scale [PedNIHSS] 0-4), were diagnosed faster post-protocol (12.1 vs 36.3h; p=0.003). Magnetic resonance imaging (MRI) was the initial diagnostic modality more often post-protocol (25% vs 1.4%; p<0.001). Initial MRI was more accurate for diagnosing stroke than initial CT (100% vs 47%; p<0.001) with similar time-to-diagnosis. The proportion of children receiving antithrombotic medication within 24 hours doubled in the post-protocol period (83% vs 36%; p<0.001).

Interpretation: A pediatric ASP accelerated time-to-treatment, time-to-diagnosis in children with subtle strokes, and increased MRI as initial imaging, reducing the need for computed tomography. Implementing optimized ASPs can facilitate more timely access to diagnosis and management of children with acute stroke.
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http://dx.doi.org/10.1111/dmcn.13214DOI Listing
January 2017

Association Between Prolonged Seizures and Malignant Middle Cerebral Artery Infarction in Children With Acute Ischemic Stroke.

Pediatr Neurol 2016 11 27;64:44-51. Epub 2016 Aug 27.

Division of Neurology, Department of Pediatrics, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada; Child Health Evaluative Sciences Program, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada.

Background: Malignant middle cerebral artery infarct syndrome is a potentially fatal complication of stroke that is poorly understood in children. We studied the frequency, associated characteristics, and outcomes of this condition in children.

Methods: Children, aged two months to 18 years with acute middle cerebral artery infarct diagnosed at our center between January 2005 and December 2012 were studied. Associations with malignant middle cerebral artery infarct syndrome were sought, including age, seizures, neurological deficit severity (Pediatric National Institute of Health Stroke Severity Score), stroke etiology, fever, blood pressure, blood glucose, infarct location, infarct volume (modified pediatric Alberta Stroke Program Early Computed Tomography Score), and arterial occlusion. Death and neurological outcomes were determined.

Results: Among 66 children with middle cerebral artery stroke, 12 (18%) developed malignant middle cerebral artery infarct syndrome, fatal in three. Prolonged seizures during the first 24 hours (odds ratio, 25.51; 95% confidence interval, 3.10 to 334.81; P = 0.005) and a higher Pediatric National Institute of Health Stroke Severity Score (odds ratio, 1.22; 95% confidence interval, 1.08 to 1.45; P = 0.006) were independently associated with malignant middle cerebral artery infarct syndrome. All children aged greater than two years with a Pediatric National Institute of Health Stroke Severity Score ≥8 and initial seizures ≥5 minutes duration developed malignant middle cerebral artery infarct syndrome (100%).

Conclusions: Malignant middle cerebral artery infarct syndrome affects nearly one in five children with acute middle cerebral artery stroke. Children with higher Pediatric National Institute of Health Stroke Severity Scores and prolonged initial seizures are at greatly increased risk for malignant middle cerebral artery infarct syndrome. Children with middle cerebral artery infarcts warrant intensive neuroprotective management and close monitoring to enable early referral for hemicraniectomy surgery.
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http://dx.doi.org/10.1016/j.pediatrneurol.2016.08.015DOI Listing
November 2016

Differential hormonal and gene expression dynamics in two inbred sunflower lines with contrasting dormancy level.

Plant Physiol Biochem 2016 May 19;102:133-40. Epub 2016 Feb 19.

Laboratorio de Fisiología Vegetal, Fac. de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), 5800, Río Cuarto, Córdoba, Argentina. Electronic address:

Seed germination and dormancy are tightly regulated by hormone metabolism and signaling pathway. We investigated the endogenous content of abscisic acid (ABA), its catabolites, and gibberellins (GAs), as well as the expression level of certain ABA and GAs metabolic and signaling genes in embryo of dry and imbibed cypselas of inbred sunflower (Helianthus annuus L., Asteraceae) lines: B123 (dormant) and B91 (non-dormant). Under our experimental conditions, the expression of RGL2 gene might be related to the ABA peak in B123 line at 3 h of imbibition. Indeed, RGL2 transcripts are absent in dry and early embedded cypselas of the non-dormant line B91. ABA increase was accompanied by a significant ABA-Glucosyl ester (ABA-GE) and phaseic acid (PA) (two ABA catabolites) decrease in B123 line (3 h) which indicates that ABA metabolism seems to be more active in this line, and that it would be involved in the imposition and maintenance of sunflower seed dormancy, as it has been reported for many species. Finally, an increase of bioactive GAs (GA1 and GA3) occurs at 12 h of imbibition in both lines after a decrease in ABA content. This study shows the first report about the RGL2 tissue-specific gene expression in sunflower inbred lines with contrasting dormancy level. Furthermore, our results provide evidence that ABA and GAs content and differential expression of metabolism and signaling genes would be interacting in seed dormancy regulation through a mechanism of action related to embryo itself.
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http://dx.doi.org/10.1016/j.plaphy.2016.02.021DOI Listing
May 2016

Early perception of stink bug damage in developing seeds of field-grown soybean induces chemical defences and reduces bug attack.

Pest Manag Sci 2016 Aug 4;72(8):1585-94. Epub 2016 Jan 4.

Cátedra de Bioquímica/Instituto de Investigaciones en Biociencias Agrícolas y Ambientales, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina.

Background: Southern green stink bugs (Nezara viridula L.) invade field-grown soybean crops, where they feed on developing seeds and inject phytotoxic saliva, which causes yield reduction. Although leaf responses to herbivory are well studied, no information is available about the regulation of defences in seeds.

Results: This study demonstrated that mitogen-activated protein kinases MPK3, MPK4 and MPK6 are expressed and activated in developing seeds of field-grown soybean and regulate a defensive response after stink bug damage. Although 10-20 min after stink bug feeding on seeds induced the expression of MPK3, MPK6 and MPK4, only MPK6 was phosphorylated after damage. Herbivory induced an early peak of jasmonic acid (JA) accumulation and ethylene (ET) emission after 3 h in developing seeds, whereas salicylic acid (SA) was also induced early, and at increasing levels up to 72 h after damage. Damaged seeds upregulated defensive genes typically modulated by JA/ET or SA, which in turn reduced the activity of digestive enzymes in the gut of stink bugs. Induced seeds were less preferred by stink bugs.

Conclusion: This study shows that stink bug damage induces seed defences, which is perceived early by MPKs that may activate defence metabolic pathways in developing seeds of field-grown soybean. © 2015 Society of Chemical Industry.
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http://dx.doi.org/10.1002/ps.4192DOI Listing
August 2016

Current concepts in pediatric stroke.

Indian J Pediatr 2015 Feb 23;82(2):179-88. Epub 2014 Nov 23.

Division of Neurology, Department of Pediatrics, University of Toronto and the Hospital for Sick Children, Toronto, Canada.

Stroke is a relatively rare but rather significant cause of short- and long-term morbidity and mortality in children. It can be divided into three categories: arterial ischemic stroke (AIS), hemorrhagic stroke (HS) and cerebral sinovenous thrombosis (CSVT). This review focuses on AIS. The etiologies of pediatric AIS are diverse and different from those in adult stroke, chief among these being congenital heart disease, vasculopathies, hematological disorders and prothrombotic states. Additional factors might be related to the age group, ethnicity and geographic factors. Early recognition enables initiation of prompt therapy thereby reducing risk of further recurrence and complications.
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http://dx.doi.org/10.1007/s12098-014-1604-3DOI Listing
February 2015

Influence of different test parameters on the microshear bond strength of two simplified etch-and-rinse adhesives.

J Adhes Dent 2014 Aug;16(4):323-31

Purpose: To evaluate the effect of different test parameters on the resin-dentin microshear bond strength (μSBS).

Materials And Methods: A 1.5-mm-thick dentin disk was prepared in each of 140 human molars. The disks were divided into five groups to test the following variables: time of adhesive light polymerization (n = 20), storage time (n = 40), bonding area (n = 40), Tygon tube removal (n = 20), and time of composite placement (n = 20). The adhesives were applied and each specimen was subjected to μSBS testing. All fractured specimens were observed with SEM. The data from each experiment were subjected to two-way ANOVA and Tukey's test (α = 0.05).

Results: The storage time, bonding area, and Tygon tube removal did not influence the μSBS. Higher μSBS values were found when empty Tygon tubes were filled after positioning and when the adhesive was light polymerized before Tygon tube placement (p < 0.05).

Conclusions: Differences in test parameters affected the μSBS of adhesives, especially the time of adhesive light polymerization and composite placement.
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http://dx.doi.org/10.3290/j.jad.a32071DOI Listing
August 2014

Six-month evaluation of a resin/dentin interface created by methacrylate and silorane-based materials.

J Appl Oral Sci 2013 Jan-Feb;21(1):80-4

University North of Paraná, Londrina, PR, Brazil.

Objectives: This study aimed to compare the micro-tensile bond strength of methacrylate resin systems to a silorane-based restorative system on dentin after 24 hours and six months water storage.

Material And Methods: The restorative systems Adper Single Bond 2/Filtek Z350 (ASB), Clearfil SE Bond/Z350 (CF), Adper SE Plus/Z350 (ASEP) and P90 Adhesive System/Filtek P90 (P90) were applied on flat dentin surfaces of 20 third molars (n=5). The restored teeth were sectioned perpendicularly to the bonding interface to obtain sticks (0.8 mm2) to be tested after 24 hours (24 h) and 6 months (6 m) of water storage, in a universal testing machine at 0.5 mm/min. The data was analyzed via two-way Analysis of Variance/Bonferroni post hoc tests at 5% global significance.

Results: Overall outcomes did not indicate a statistical difference for the resin systems (p=0.26) nor time (p=0.62). No interaction between material × time was detected (p=0.28). Mean standard-deviation in MPa at 24 h and 6 m were: ASB 31.38 (4.53) and 30.06 (1.95), CF 34.26 (3.47) and 32.75 (4.18), ASEP 29.54 (4.14) and 33.47 (2.47), P90 30.27 (2.03) and 31.34 (2.19).

Conclusions: The silorane-based system showed a similar performance to methacrylate-based materials on dentin. All systems were stable in terms of bond strength up to 6 month of water storage.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3881815PMC
http://dx.doi.org/10.1590/1678-7757201302329DOI Listing
June 2013

Expanding the Spectrum of Methylmalonic Acid-Induced Pallidal Stroke: First Reported Case of Metabolic Globus Pallidus Stroke in Transcobalamin II Deficiency.

JIMD Rep 2013 21;11:7-11. Epub 2013 Feb 21.

Division of Neurology, University of Toronto, Toronto, Canada, M5G 1X8,

Unlabelled: A 10-year-old boy with transcobalamin II (TCII) deficiency on oral cyanocobalamin therapy presented with acute right hemiparesis and sensory axonal neuropathy in the context of an intercurrent viral illness. MRI demonstrated unilateral globus pallidus stroke with normal MRA. Echocardiogram was normal. Methylmalonic acid in serum was mildly elevated at 10.29 μmol/L (normal < 0.37 μmol/L), which was an 18-fold increase from his previous baseline. The patient was switched to IM cyanocobalamin and serum methylmalonic acid levels normalized over 6 months to 0.01 μmol/L. After 4 months of IM cyanocobalamin therapy, the neuropathy had resolved. Repeat MRI 4 months after the sentinel stroke demonstrated a chronic-appearing contralateral globus pallidus stroke of uncertain timing.

Conclusions: We are describing the first case of metabolic stroke and peripheral neuropathy in TCII deficiency. The neuropathy was responsive to parenteral hydroxycobalamin. Unilateral globus pallidus stroke in the appropriate clinical context should not exclude a metabolic etiology as it may herald contralateral involvement and may provide an opportunity for early recognition and treatment. IM hydroxycobalamin should be strongly considered in all patients with TCII, particularly when they reach later childhood. This case highlights the selective vulnerability of the globus pallidus to increased levels of methylmalonic acid of various causes, which is important for both diagnosis and ultimately understanding the mechanisms of neurological injury in this group of conditions. Metabolic stroke may occur with lower levels of methylmalonic acid than previously reported in the context of an intercurrent bioenergetic stressor.
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http://dx.doi.org/10.1007/8904_2013_215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3755557PMC
August 2013

Do the microshear test variables affect the bond strength values?

Int J Dent 2012 4;2012:618960. Epub 2012 Nov 4.

Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, Cidade Universitária, 05508-000 São Paulo, SP, Brazil.

Little is known about the effect of specimen preparation and testing protocols on the micro-shear bond strength (μSBS) results. To evaluate whether variations in polyethylene rod use affect (μSBS)). Human dentin disks were randomly distributed into six groups (n = 5): polyethylene tube (3 levels) and adhesive system (2 levels). In Group 1, polyethylene tubes filled with polymerized composite) were placed on adhesive covered surfaces. Tubes were removed 24 h after water storage, leaving the rods only. In Group 2, the same procedure was performed; however, tubes were kept in place during testing. In Group 3, composite rods without tubes were placed on adhesive covered dentin. In all groups, adhesives were photoactivated after positioning filled tubes/rods on adhesive covered surfaces. Specimens were tested under shear mode and the data subjected to a two-way ANOVA and Tukey's tests. Groups 1 and 2 resulted in statistically similar mean μSBS (P > 0.05); however, a greater number of pretest failures were observed for Group 1. Higher μSBS values were detected for Group 3, irrespective of adhesive system used (P < 0.05). Removing the polyethylene tube before composite rod is placed on dentin affects μSBS values.
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http://dx.doi.org/10.1155/2012/618960DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3502005PMC
November 2012

Effect of surface area and air-drying distance on shear bond strength of etch-and-rinse adhesive.

Braz Oral Res 2012 Sep-Oct;26(5):418-23. Epub 2012 Jul 19.

Operative Dentistry Department, Faculty of Dentistry, Ain Shams University, Cairo, Egypt.

We evaluated the effects of air-drying distance and bond surface area on the shear bond strength of a 2-step etch-and-rinse adhesive. A total of 120 bovine anterior teeth were equally divided into 6 main groups based on bonding surface area. The main groups were divided into sub-groups (n = 5) according to air-drying distance. The shear strength was determined using a universal testing machine at a crosshead speed of 0.5 mm/min. The averaged results were subjected to two-way ANOVA and Tukey's test (α = 0.05). Two-way ANOVA testing identified no significant cross-product interactions (p > 0.05), but the main factors of area (p < 0.0001) and air-drying distance (p < 0.00001) significantly affected the mean bond strength. Shorter air-drying distances improved bond strength, and increased surface area decreased the bond strength.
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http://dx.doi.org/10.1590/s1806-83242012005000013DOI Listing
March 2013

Immediate bonding to bleached enamel treated with 10% sodium ascorbate gel: a case report with one-year follow-up.

Eur J Esthet Dent 2012 ;7(2):154-62

Department of Dental Materials, University of Sao Paulo, Sao Paulo, SP, Brazil.

It is generally not recommended that bonded restoration treatment should be carried out immediately after bleaching treatment. However, the use of antioxidants such as sodium ascorbate can be useful to avoid a waiting period. This article is a brief review about in vitro proposals to overcome low bond strength values to bleached dental surfaces. It shows a one-year follow-up case report of a young female presenting agenesis of maxillary lateral incisors reshaped with direct resin composite immediately after dental bleaching. Teeth were bleached with a combination of in-office and at-home whitening protocols, followed by the application of a 10% sodium ascorbate gel for one hour, to allow the immediate reshaping with direct resin composite restoration. After one year, the clinical performance of the restoration was successful. The use of sodium ascorbate gel can help the clinician to perform bonding procedures immediately after bleaching treatments.
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July 2012