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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.
Multiple genes/variants have been implicated in various epileptic conditions. However, there is little general guidance available on the circumstances in which genetic testing is indicated and test selection in order to guide optimal test appropriateness and benefit. This is an account of the development of guidelines for genetic testing in epilepsy, which have been developed in Ontario, Canada. The Genetic Testing Advisory Committee was established in Ontario to review the clinical utility and validity of genetic tests and the provision of genetic testing in Ontario. As part of their mandate, the committee also developed recommendations and guidelines for genetic testing in epilepsy. The recommendations include mandatory prerequisites for an epileptology/geneticist/clinical biochemical geneticist consultation, prerequisite diagnostic procedures, circumstances in which genetic testing is indicated and not indicated and guidance for selection of genetic tests, including their general limitations and considerations. These guidelines represent a step toward the development of evidence-based gene panels for epilepsy in Ontario, the repatriation of genetic testing for epilepsy into Ontario molecular genetic laboratories and public funding of genetic tests for epilepsy in Ontario.
We investigated risk factors for severe acute lower respiratory infections (ALRI) among hospitalised children <2 years, with a focus on the interactions between virus and age. Statistical interactions between age and respiratory syncytial virus (RSV), influenza, adenovirus (ADV) and rhinovirus on the risk of ALRI outcomes were investigated. Of 1780 hospitalisations, 228 (12.8%) were admitted to the intensive care unit (ICU). The median (range) length of stay (LOS) in hospital was 3 (1–27) days. An increase of 1 month of age was associated with a decreased risk of ICU admission (rate ratio (RR) 0.94; 95% confidence intervals (CI) 0.91–0.98) and with a decrease in LOS (RR 0.96; 95% CI 0.95–0.97). Associations between RSV, influenza, ADV positivity and ICU admission and LOS were significantly modified by age. Children <5 months old were at the highest risk from RSV-associated severe outcomes, while children >8 months were at greater risk from influenza-associated ICU admissions and long hospital stay. Children with ADV had increased LOS across all ages. In the first 2 years of life, the effects of different viruses on ALRI severity varies with age. Our findings help to identify specific ages that would most benefit from virus-specific interventions such as vaccines and antivirals.
Multiple sulfatase deficiency (MSD) is a rare autosomal recessive inborn error of lysosomal metabolism. The clinical phenotypic spectrum encompasses overlapping features of variable severity and is suggestive of individual single sulfatase deficiencies (i.e., metachromatic leukodystrophy, mucopolysaccharidosis, and X-linked ichthyosis).
We describe a 3-year-old male with severe hypotonia, developmental regression and progressive neurodegeneration, coarse facial features, nystagmus (from ocular albinism), and dysmyelinating motor sensory neuropathy. Ethics approval was obtained from the Western University Ontario.
Extensive investigative work-up identified deficiencies of multiple sulfatases: heparan sulfate sulfamidase: 6.5 nmoles/mg/protein/17 hour (reference 25.0-75.0), iduronate-2-sulfate sulfatase: 9 nmol/mg/protein/4 hour (reference 31-110), and arylsulfatase A: 3.8 nmoles/hr/mg protein (reference 22-50). The identification of compound heterozygous pathogenic mutations in the SUMF1 gene c.836 C>T (p.A279V) and c.1045C>T (p.R349W) confirmed the diagnosis of MSD.
The complex clinical manifestations of MSD and the unrelated coexistence of ocular albinism as in our case can delay diagnosis. Genetic counselling should be provided to all affected families.
To assess subjective preference using three nasal hygiene systems: Stérimar Original®, Emcur® and Sinus Rinse™.
We used a prospective, single-blind, randomised, crossover study to compare three nasal hygiene systems: Stérimar Original, Emcur and Sinus Rinse.
Eighteen adult volunteers were recruited and were asked to rate their experience over three days using three well-established nasal hygiene systems. A standard visual analogue scale was used to assess five criteria: (1) simplicity of instructions; (2) ease of use; (3) comfort; (4) perceived nasal clearance (effectiveness) and (5) single best overall system.
Stérimar Original was found to have the easiest instructions to understand compared to the other two systems. There was no significant difference between Stérimar Original and Sinus Rinse with regards to ease of use but they were both significantly easier to use than Emcur (p < 0.05). There was no statistically significant difference between the three systems when comparing the last three criteria. There was no alteration in preference when the cost of each treatment was disclosed to the subjects, and no significant side effects were reported.
The instructions accompanying Stérimar Original appeared to be the easiest to understand, while Stérimar Original and Sinus Rinse were easier to use than Emcur.
The epileptic encephalopathies of infancy are a group of disorders characterized by intractable seizures, persistent abnormality of cortical function documented on EEG, and consequently impaired neuro-developmental outcomes. The etiologies vary and include; structural brain malformations, acquired brain insults, and inborn errors of metabolism in the majority of the affected patients. In a proportion of these cases no obvious etiology is identifiable on investigation. Recent advances in molecular diagnostics have led to the discovery of a number of gene defects that may be causal in many epileptic encephalopathies. Identification of the causative mutation is important for prognostic and genetic counseling, and may also carry treatment implications. The recently described genes include; Cyclin-Dependent Kinase-Like 5 gene (CDKL5), Protocadherin 19 (PCDH19), Sodium channel neuronal type 1a subunit gene (SCN1A), Aristaless-Related Homeobox Gene (ARX), and Syntaxin binding protein 1 gene (STXBP1), amongst others. Distinct electro-clinical syndromes are increasingly being identified amongst patients carrying the various mutations. In this review, we outline the approach to clinical evaluation and genetic testing of epileptic encephalopathies in infancy.
N-acetyl-glutamate synthase (NAGS) deficiency is a rare autosomal recessive urea cycle disorder (UCD) that uncommonly presents in adulthood. Adult presentations of UCDs include; confusional episodes, neuropsychiatric symptoms and encephalopathy. To date, there have been no detailed neurological descriptions of an adult onset presentation of NAGS deficiency. In this review we examine the clinical presentation and management of UCDs with an emphasis on NAGS deficiency. An illustrative case is provided. Plasma ammonia levels should be measured in all adult patients with unexplained encephalopathy, as treatment can be potentially life-saving. Availability of N-carbamylglutamate (NCG; carglumic acid) has made protein restriction largely unnecessary in treatment regimens currently employed. Genetic counselling remains an essential component of management of NAGS.
The paper attempts to present a panoramic view of the water cement ratio strength relations adopted by a few national bodies and look at the appropriateness of them while keeping in mind the enormous number of variables that could influence them. These relations are also compared with a couple of databases reported to assess the efficacy of each of these in ensuring a reasonable prediction capability. This in a way will pave the way for an effective use of the cement in concrete leading to significant optimization of the concrete composite.
Herpes virus infections can cause cognitive impairment during and after acute encephalitis. Although chronic, latent/persistent infection is considered to be relatively benign, some studies have documented cognitive impairment in exposed persons that is untraceable to encephalitis. These studies were conducted among schizophrenia (SZ) patients or older community dwellers, among whom it is difficult to control for the effects of co-morbid illness and medications. To determine whether the associations can be generalized to other groups, we examined a large sample of younger control individuals, SZ patients and their non-psychotic relatives (n=1852).
Using multivariate models, cognitive performance was evaluated in relation to exposures to herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2) and cytomegalovirus (CMV), controlling for familial and diagnostic status and sociodemographic variables, including occupation and educational status. Composite cognitive measures were derived from nine cognitive domains using principal components of heritability (PCH). Exposure was indexed by antibodies to viral antigens.
PCH1, the most heritable component of cognitive performance, declines with exposure to CMV or HSV-1 regardless of case/relative/control group status (p = 1.09 × 10−5 and 0.01 respectively), with stronger association with exposure to multiple herpes viruses (β = −0.25, p = 7.28 × 10−10). There were no significant interactions between exposure and group status.
Latent/persistent herpes virus infections can be associated with cognitive impairments regardless of other health status.
Matrix metalloproteinases (MMPs) are the major endopeptidases involved in proteolysis of blood brain barrier (BBB) during central nervous system (CNS) infections. The present study detected serum levels and activities of MMP-2 and MMP-9 in patients with neurocysticercosis (NCC) and their association with symptomatic disease. In total, 68 individuals with NCC (36 symptomatic patients with active seizures and 32 asymptomatic individuals) and 37 healthy controls were enrolled for the study. Serum MMP-2 and MMP-9 levels and their activities were measured by ELISA and gel zymography respectively. Mean serum MMP-2 levels (ng/ml) were higher both in asymptomatic and symptomatic NCC cases compared to healthy controls. However, significantly higher levels of serum MMP-9 (ng/ml) were detected only in symptomatic NCC patients compared to asymptomatic NCC cases and healthy controls. Levels of both MMPs positively correlated with symptomatic NCC. Serum MMP-2 activities were significantly higher in symptomatic and asymptomatic NCC compared to healthy controls whereas serum MMP-9 activity was significantly associated with symptomatic NCC compared to healthy controls and asymptomatic NCC. In conclusion, the elevated level of MMP-9 in serum appears to play an important role in the development of symptoms i.e. active seizures in patients with NCC. However, further studies are needed to elucidate its precise role in disease pathogenesis.
We report the binding and conductivity characteristics of PbSe nanocrystal quantum dots which have different ligands on the surface. The PbSe nanocrystal quantum dots were surface functionalized using chemical treatment. The results of post-treatment analysis show that the PbSe surface can be successfully functionalized with various ligands based on thiol- and amine-molecules (e.g., oleic acid, dodecanethiol and butylamine). Conductivity measurements performed using a metal-semiconductor-metal structure indicate that there is an increase of conductivity as the length of the ligand connecting the quantum dots is reduced.
We presented in this paper a photo-assisted ligand exchange approach whereby
light will be introduced to facilitate the replacement of oleic acid (OA)
ligand molecules over PbSe quantum dots (QDs). The ligand-exchanged QDs were
used to fabricate quantum dot light-emitting-diodes (QD-LEDs), which
outperform the devices comprising the QDs without ligand-replacement.
The newly emerging field of Nonlinear Optics and Photonics offers tremendous opportunities for material scientists. In this paper, chemical processing using the sol-gel method is described for the preparation of new composite materials of both a silica glass and a V2O5 gel with a wπ conjugated polymer poly-p-phenylene vinylene up to 5d% by weight. The composite films show highly improved optical quality with large third-order nonlinear optical coefficients, the latter from the conjugated polymer. Optical waveguiding through the film has been achieved. Nonlinear optical studies using femtosecond degenerate four wave mixing and power dependent waveguide coupling have been successfully performed. Also, to investigate the use of such films for optical recording, a two-dimensional grating structure has successfully been produced.
The preparation of hydrogenated amorphous silicon by the radio-frequency (RF) glow discharge technique is shown to be strongly dependent on the plasma excitation frequency. We have investigated the influence of this parameter on the deposition rate, on the hydrogen content and on the opto-electronic properties of the amorphous silicon films, over the range 25 to 150 MHz. A large variation of the deposition rate is observed, while most of the material properties remain practically unchanged. The results should be of considerable interest for mass production of low-cost amorphous silicon thin film devices.
Picosecond and femtosecond degenerate four-wave mixing have been used to measure third-order nonlinear optical susceptibility of several rigid-rod polymers and model compounds. A significant X(3) with femtosecond response was observed. The effects of processing conditions and structural variations on X(3) were studied. Four-wave mixing studies can also be conveniently used to generate ultrasonic phonons of well defined wave length and propagation direction. From this result one can investigate mechanical properties of polymers. Using this technique both the longitudinal and shear components of the elastic moduli for a uniaxially oriented rigid-rod polymer, poly-p-phenylene bis benzooxazole (PBO), were determined.
This paper presents some recent theoretical and experimental work carried out in the author's laboratory on the nonlinear optical properties of organic polymers. The ab initio SCF theory has been used with the finite field method to calculate the third order nonlinearity of conjugated structures in order to understand the effect of conjugation and the role of substituents. Experimental studies of third order resonant nonlinearlty in polythiophenes and cumylphenoxy phthalocyanine, the latter in the form of Langmuir-Blodgett films, are presented using femtosecond degenerate four wave mixing.
Molecular units in natural systems are multifunctional in that they exhibit more than one functionalities. This is nature's way of economizing and being efficient. For many technological applications, there is a need for synthetic multifunctional materials which simultaneously exhibit many necessary physical and chemical properties. By appropriate modification of structures both at the molecular and bulk levels, one can incorporate such multifunctionality in molecular and polymeric systems. Our research program focuses on investigations of multifunctional materials for applications in photonics. Photonics describes the emerging new technology in which a photon instead of an electron is used to acquire, process, store and transmit information.