Immature Spinal Locomotor Output in Children with Cerebral Palsy

Detailed descriptions of gait impairments have been reported in cerebral palsy (CP), but it is still unclear how maturation of the spinal motoneuron output is affected. Spatiotemporal alpha-motoneuron activation during walking can be assessed by mapping the electromyographic activity profiles from several, simultaneously recorded muscles onto the anatomical rostrocaudal location of the motoneuron pools in the spinal cord, and by means of factor analysis of the muscle activity profiles. Here, we analyzed gait kinematics and EMG activity of 11 pairs of bilateral muscles with lumbosacral innervation in 35 children with CP (19 diplegic, 16 hemiplegic, 2-12 years) and 33 typically developing (TD) children (1-12 years). TD children showed a progressive reduction of EMG burst durations and a gradual reorganization of the spatiotemporal motoneuron output with increasing age. By contrast, children with CP showed very limited age-related changes of EMG durations and motoneuron output, as well as of limb intersegmental coordination and foot trajectory control (on both sides for diplegic children and the affected side for hemiplegic children). Factorization of the EMG signals revealed a comparable structure of the motor output in children with CP and TD children, but significantly wider temporal activation patterns in children with CP, resembling the patterns of much younger TD infants. A similar picture emerged when considering the spatiotemporal maps of alpha-motoneuron activation. Overall, the results are consistent with the idea that early injuries to developing motor regions of the brain substantially affect the maturation of the spinal locomotor output and consequently the future locomotor behavior.

Ambient and Dosed Exposure to Quaternary Ammonium Disinfectants Causes Neural Tube Defects in Rodents

Background

Quaternary ammonium compounds are a large class of chemicals used for their antimicrobial and antistatic properties. Two common quaternary ammonium compounds, alkyldimethylbenzyl ammonium chloride (ADBAC) and didecyldimethyl ammonium chloride (DDAC), are combined in common cleaners and disinfectants. Introduction of a cleaner containing ADBAC+DDAC in the vivarium caused neural tube defects (NTDs) in mice and rats.

Methods

To further evaluate this finding, male and female mice were dosed in the feed at 60 or 120 mg/kg/day, or by oral gavage at 7.5, 15, or 30 mg/kg ADBAC+DDAC. Mice also received ambient exposure to ADBAC+DDAC from the disinfectant used in the mouse room. Embryos were evaluated on gestational day 10 for NTDs, and fetuses were evaluated on gestational day 18 for gross and skeletal malformations.

Results

We found increased NTDs with exposure to ADBAC+DDAC in both rats and mice. The NTDs persisted for two generations after cessation of exposure. Notably, male exposure alone was sufficient to cause NTDs. Equally significant, ambient exposure from disinfectant use in the vivarium, influenced the levels of NTDs to a greater extent than oral dosing. No gross or significant axial skeletal malformations were observed in late gestation fetuses. Placental abnormalities and late gestation fetal deaths were increased at 120 mg/kg/day, which might explain the lack of malformations observed in late gestation fetuses.

Conclusion

These results demonstrate that ADBAC+DDAC in combination are teratogenic to rodents. Given the increased use of these disinfectants, further evaluation of their safety in humans and their contribution to health and disease is essential.

The N-terminal acetyltransferase Naa10 is essential for zebrafish development

The Naa10 (Nα acetyltransferase 10) N-terminal acetyltransferase is implicated in cancer and developmental syndromes in humans. We show that its enzymatic activity is conserved in zebrafish, and that Naa10 depletion leads to developmental abnormalities.

N-terminal acetylation, catalysed by N-terminal acetyltransferases (NATs), is among the most common protein modifications in eukaryotes and involves the transfer of an acetyl group from acetyl-CoA to the α-amino group of the first amino acid. Functions of N-terminal acetylation include protein degradation and sub-cellular targeting. Recent findings in humans indicate that a dysfunctional Nα-acetyltransferase (Naa) 10, the catalytic subunit of NatA, the major NAT, is associated with lethality during infancy. In the present study, we identified the Danio rerio orthologue zebrafish Naa 10 (zNaa10). In vitro N-terminal acetylation assays revealed that zNaa10 has NAT activity with substrate specificity highly similar to that of human Naa10. Spatiotemporal expression pattern was determined by in situ hybridization, showing ubiquitous expression with especially strong staining in brain and eye. By morpholino-mediated knockdown, we demonstrated that naa10 morphants displayed increased lethality, growth retardation and developmental abnormalities like bent axis, abnormal eyes and bent tails. In conclusion, we identified the zebrafish Naa10 orthologue and revealed that it is essential for normal development and viability of zebrafish.

Maturation of the Locomotor Circuitry in Children With Cerebral Palsy

The first years of life represent an important phase of maturation of the central nervous system, processing of sensory information, posture control and acquisition of the locomotor function. Cerebral palsy (CP) is the most common group of motor disorders in childhood attributed to disturbances in the fetal or infant brain, frequently resulting in impaired gait. Here we will consider various findings about functional maturation of the locomotor output in early infancy, and how much the dysfunction of gait in children with CP can be related to spinal neuronal networks vs. supraspinal dysfunction. A better knowledge about pattern generation circuitries in infancy may improve our understanding of developmental motor disorders, highlighting the necessity for regulating the functional properties of abnormally developed neuronal locomotor networks as a target for early sensorimotor rehabilitation. Various clinical approaches and advances in biotechnology are also considered that might promote acquisition of the locomotor function in infants at risk for locomotor delays.

Clinical Relevance of State-of-the-Art Analysis of Surface Electromyography in Cerebral Palsy

Surface electromyography (sEMG) can be used to assess the integrity of the neuromuscular system and its impairment in neurological disorders. Here we will consider several issues related to the current clinical applications, difficulties and limited usage of sEMG for the assessment and rehabilitation of children with cerebral palsy. The uniqueness of this methodology is that it can determine hyperactivity or inactivity of selected muscles, which cannot be assessed by other methods. In addition, it can assist for intervention or muscle/tendon surgery acts, and it can evaluate integrated functioning of the nervous system based on multi-muscle sEMG recordings and assess motor pool activation. The latter aspect is especially important for understanding impairments of the mechanisms of neural controllers rather than malfunction of individual muscles. Although sEMG study is an important tool in both clinical research and neurorehabilitation, the results of a survey on the clinical relevance of sEMG in a typical department of pediatric rehabilitation highlighted its limited clinical usage. We believe that this is due to limited knowledge of the sEMG and its neuromuscular underpinnings by many physiotherapists, as a result of lack of emphasis on this important methodology in the courses taught in physical therapy schools. The lack of reference databases or benchmarking software for sEMG analysis may also contribute to the limited clinical usage. Despite the existence of educational and technical barriers to a widespread use of, sEMG does provide important tools for planning and assessment of rehabilitation treatments for children with cerebral palsy.

Abnormal Development of Hyalomma Marginatum Ticks (Acari: Ixodidae) Induced by Plant Cytotoxic Substances

The increasing application of toxic plant substances to deter and fight ticks proves the need for investigations focused on the elucidation of their impact on the developmental stages and populations of these arthropods. We examined the course of embryogenesis and egg hatch in Hyalomma marginatum ticks under the effect of cytotoxic plant substances. The investigations demonstrated that the length of embryonic development of egg batches treated with 20 μL of a 0.1875% colchicine solution did not differ significantly from that in the control group. Colchicine caused the high mortality of eggs (16.3%) and embryos (9.7%), disturbances in larval hatch (8.1%), and lower numbers of normal larval hatches (65.6%). In 0.2% of the larvae, colchicine induced anomalies in the idiosoma (67.6%) and gnathosoma (22.5%) as well as composite anomalies (8.5%). The study demonstrates that cytotoxic compounds with an effect similar to that of colchicine can reduce tick populations and cause teratological changes, which were observed in the specimens found during field studies. Since there are no data on the toxic effects of active plant substances on other organisms and the risk of development of tick resistance, a strategy for the use of such compounds in tick control and the management of plant products should be developed.

Developmental Alterations in Cortical Organization and Socialization in Adolescents Who Sustained a Traumatic Brain Injury in Early Childhood

This study investigated patterns of cortical organization in adolescents who had sustained a traumatic brain injury (TBI) during early childhood to determine ways in which early head injury may alter typical brain development. Increased gyrification in other patient populations is associated with polymicrogyria and aberrant development, but this has not been investigated in TBI. Seventeen adolescents (mean age = 14.1 ± 2.4) who sustained a TBI between 1-8 years of age, and 17 demographically-matched typically developing children (TDC) underwent a high-resolution, T1-weighted 3-Tesla magnetic resonance imaging (MRI) at 6-15 years post-injury. Cortical white matter volume and organization was measured using FreeSurfer's Local Gyrification Index (LGI). Despite a lack of significant difference in white matter volume, participants with TBI demonstrated significantly increased LGI in several cortical regions that are among those latest to mature in normal development, including left parietal association areas, bilateral dorsolateral and medial frontal areas, and the right posterior temporal gyrus, relative to the TDC group. Additionally, there was no evidence of increased surface area in the regions that demonstrated increased LGI. Higher Vineland-II Socialization scores were associated with decreased LGI in right frontal and temporal regions. The present results suggest an altered pattern of expected development in cortical gyrification in the TBI group, with changes in late-developing frontal and parietal association areas. Such changes in brain structure may underlie cognitive and behavioral deficits associated with pediatric TBI. Alternatively, increased gyrification following TBI may represent a compensatory mechanism that allows for typical development of cortical surface area, despite reduced brain volume.

[Progress on abnormal development of cloned pigs generated by somatic cell transfer nuclear]

Cloning, also known as somatic cell nuclear transfer (SCNT), is an asexual reproduction technique that reprograms differentiated cells to the totipotent state, and generates offspring with a genotype identical to the donor cells. Pig cloning technique holds great promise for propagating excellent breeding boars, generating genetically modified pigs, protecting rare and endangered pigs and studying the mechanisms of somatic cell nucleus reprogramming. However, cloned pigs suffer from various developmental defects, including low birth rate, low birth weight, and high stillbirth occurrence, neonatal mortality and congenital malformations, which severely hamper their applications. Errors in epigenetic reprogramming of donor nucleus are considered as the main causes of low cloning efficiency and abnormal embryonic development in cloned embryos and animals. However, most studies to correct the errors in epigenetic reprogramming of cloned pig embryos have not substantially improved the birth and survival rates of cloned pigs. In this review, we summarize the abnormal phenotypes, causes of abnormal development of cloned pigs and effective methods for improving pig cloning efficiency, thereby providing a reference for the future research to improve the development and survival rates of cloned pig embryos and cloned pigs.

Sargassum fusiforme polysaccharide attenuates high-sugar-induced lipid accumulation in HepG2 cells and Drosophila melanogaster larvae

Lipid accumulation is a major factor in the development of non-alcoholic fatty liver disease (NAFLD). Currently, there is a lack of intervention or therapeutic drugs against NAFLD. In this study, we investigated the ability of Sargassum fusiforme polysaccharide (SFPS) to reduce lipid accumulation induced by high sugar in HepG2 cells and Drosophila melanogaster larvae. The results indicated that SFPS significantly (p < .01) decreased the accumulation of lipid droplets in high sugar-induced HepG2 cells. Furthermore, SFPS also suppressed the expression of Srebp and Fas (genes involved in lipogenesis) and increased the expression of PPARɑ and Cpt1 (genes that participated in fatty acid β-oxidation) in these cells. SFPS markedly reduced the content of triglyceride of the third instar larvae developed from D. melanogaster eggs reared on the high-sucrose diet. The expression of the Srebp and Fas genes in the larvae was also inhibited whereas the expression of two genes involved in the β-oxidation of fatty acids, Acox57D-d and Fabp, was increased in the larval fat body (a functional homolog of the human liver). We also found that SFPS ameliorated developmental abnormalities induced by the high-sucrose diet. These results of this study suggest that SFPS could potentially be used as a therapeutic agent for the prevention and treatment of NAFLD.

Abnormal Development of Haemaphysalis qinghaiensis (Acari: Ixodidae)

A single Haemaphysalis qinghaiensis specimen exhibiting abnormal morphology was collected from a tick laboratory colony. The tick had a heart-shaped body with partial twinning of the posterior region (with two anal orifices and two genital grooves). To the best of our knowledge, this is the first report of teratological changes in H. qinghaiensis The abnormal morphological features are described herein.

The ESSENCE-Questionnaire in Medical Records Screening for Neurodevelopmental Symptoms/Problems: Utility and Clinical Validity

PURPOSE

Determine the prevalence of symptoms of neurodevelopmental problems (NDPs) with a semi-structured review of fourth grade students' medical records, its interrater agreement and validity as compared with clinical assessment.

METHODS

A school-based sample of 11-year-old children provided child health care (CHC) records and school health care (SHC) records. A pediatric neurologist, child psychiatrist and an adult psychiatrist scored the records, with the "Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations-Questionnaire" (ESSENCE-Q, 12 items scored 0-2, summary score range 0-24). Agreement was measured with model-based kappa and intraclass correlation coefficient (ICC). Ratings were validated against a multidisciplinary assessment involving a physician, psychologist, teacher- and parental behavioral rating scales rendering a clinical global impression severity rating (CGI-S, range 1-7) of NDPs.

RESULTS

Out of 223 participants, medical charts were available from 201, of whom 169 were rated by all three raters. Kappa agreement was moderate/strong (~0.8) for 7 of the 12 questionnaire items. Measured with the ICC, concordance in the summary score was good for agreement (~0.8) and excellent (~0.9) for consistency. Test-retest reliability was excellent (ICC = ~0.9). Area under the curve for the ESSENCE-Q in predicting clinical-level problems (CGI ≥4) was ~80% for all three raters, albeit with differing optimal cutoffs.

CONCLUSION

Using the ESSENCE-Q as a template, NDPs appear to be common in medical records, are identified reliably, and predict clinical-level concern. Medical records screening may facilitate a structured review of medical records in work-ups or be applied in conjunction with other screening measures for neurodevelopmental disorders. However, differences in calibration currently preclude defining a universal cutoff for using the ESSENCE-Q for medical records screening.