The Cyprus Institute of Neurology and Genetics

Nicosia, Cyprus

The Cyprus Institute of Neurology and Genetics

Nicosia, Cyprus
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Spanaki C.,University of Crete | Kotzamani D.,University of Crete | Kleopa K.,The Cyprus Institute of Neurology and Genetics | Plaitakis A.,University of Crete
Molecular Neurobiology | Year: 2016

Human hGDH2 arose via duplication in the apes and driven by positive selection acquired enhanced catalytic ability under conditions inhibitory to its precursor hGDH1 (common to all mammals). To explore the biological advantage provided by the novel enzyme, we studied, by immunohistochemistry (IHC) and immunofluorescence (IF), hGDH1 and hGDH2 expression in the human brain. Studies on human cortical tissue using anti-hGDH1-specific antibody revealed that hGDH1 was expressed in glial cells (astrocytes, oligodendrocytes, and oligodendrocyte precursors) with neurons being devoid of hGDH1 staining. In contrast, an hGDH2-specific antiserum labeled both astrocytes and neurons. Specifically, hGDH2 immunoreactivity was found in the cytoplasm of large neuronal cells within coarse structures resembling mitochondria. These were distributed either in the perikaryon or in the cell periphery. Double immunofluorescence (IF) suggested that the latter represented hGDH2-labeled mitochondria of presynaptic nerve terminals. Hence, hGDH2 evolution bestowed large human neurons with enhanced glutamate metabolizing capacity, thus strengthening cortical excitatory transmission. © 2015, Springer Science+Business Media New York.

Papageorgiou E.A.,The Cyprus Institute of Neurology and Genetics | Papageorgiou E.A.,NIPD Genetics Ltd | Patsalis P.C.,The Cyprus Institute of Neurology and Genetics
Genome Medicine | Year: 2012

Non-invasive prenatal diagnosis (NIPD) has substantial medical importance as it targets the development of safer and more effective methods to avoid the risk of fetal loss associated with currently used invasive methods. Several approaches have been demonstrated as being proof-of concept for NIPD of chromosomal aneuploidies. These approaches include cell-based and cell-free detection methods, involving the investigation of fetal cells in the maternal circulation, formaldehyde treatment of maternal plasma, DNA methylation studies using sodium bisulfite or restriction enzymes, protein-based studies, identification of fetal-specific mRNAs and digital polymerase chain reaction (PCR) approaches, and recently next-generation sequencing and methylated DNA immunoprecipitation real-time quantitative PCR-based approaches. Although all these NIPD methods have both advantages and limitations, some are moving closer to clinical implementation. Biotechnology companies dedicated to the development of NIPD tests such as the sequencing- or methylation-based approaches are finalizing large clinical trials. It is expected that these new technologies will facilitate safer, more sensitive and accurate prenatal diagnostic tests in the near future. In this review, we highlight the most recent advances in methods for NIPD of aneuploidies, and we discuss their future implications in clinical practice. © 2012 BioMed Central Ltd.

Vasquez M.I.,University of Cyprus | Lambrianides A.,The Cyprus Institute of Neurology and Genetics | Schneider M.,Lüneburg University | Kummerer K.,Lüneburg University | Fatta-Kassinos D.,University of Cyprus
Journal of Hazardous Materials | Year: 2014

Cocktails of pharmaceuticals are released in the environment after human consumption and due to the incomplete removal at the wastewater treatment plants. Pharmaceuticals are considered as contaminants of emerging concern and, a plethora of journal articles addressing their possible adverse effects have been published during the past 20 years. The emphasis during the early years of research within this field, was on the assessment of acute effects of pharmaceuticals applied singly, leading to results regarding their environmental risk, potentially not realistic or relevant to the actual environmental conditions. Only recently has the focus been shifted to chronic exposure and to the assessment of cocktail effects. To this end, this review provides an up-to-date compilation of 57 environmental and human toxicology studies published during 2000-2014 dealing with the adverse effects of pharmaceutical mixtures. The main challenges regarding the design of experiments and the analysis of the results regarding the effects of pharmaceutical mixtures to different biological systems are presented and discussed herein. The gaps of knowledge are critically reviewed highlighting specific future research needs and perspectives. © 2014 Elsevier B.V.

Fanis P.,The Cyprus Institute of Neurology and Genetics | Kousiappa I.,The Cyprus Institute of Neurology and Genetics | Phylactides M.,The Cyprus Institute of Neurology and Genetics | Kleanthous M.,The Cyprus Institute of Neurology and Genetics
BMC Genomics | Year: 2014

Background: B-thalassaemia and sickle cell disease (SCD) are two of the most common monogenic diseases that are found in many populations worldwide. In both disorders the clinical severity is highly variable, with the persistence of fetal haemoglobin (HbF) being one of the major ameliorating factors. HbF levels are affected by, amongst other factors, single nucleotide polymorphisms (SNPs) at the BCL11A gene and the HBS1L-MYB intergenic region, which are located outside the β-globin locus. For this reason, we developed two multiplex assays that allow the genotyping of SNPs at these two genomic regions which have been shown to be associated with variable HbF levels in different populations.Results: Two multiplex assays based on the SNaPshot minisequencing approach were developed. The two assays can be used to simultaneous genotype twelve SNPs at the BCL11A gene and sixteen SNPs at HBS1L-MYB intergenic region which were shown to modify HbF levels. The different genotypes can be determined based on the position and the fluorescent colour of the peaks in a single electropherogram. DNA sequencing and restriction fragment length polymorphism (PCR-RFLP) assays were used to verify genotyping results obtained by SNaPshot minisequencing.Conclusions: In summary, we propose two multiplex assays based on the SNaPshot minisequencing approach for the simultaneous identification of SNPs located at the BCL11A gene and HBS1L-MYB intergenic region which have an effect on HbF levels. The assays can be easily applied for accurate, time and cost efficient genotyping of the selected SNPs in various populations. © 2014 Fanis et al.; licensee BioMed Central Ltd.

Patsalis P.C.,The Cyprus Institute of Neurology and Genetics
Applied and Translational Genomics | Year: 2012

During the last decade, the area of non-invasive prenatal diagnosis (NIPD) has rapidly evolved. Several methodological approaches have been presented and demonstrated a proof of concept for the NIPD of chromosomal aneuploidies. The two most promising methods are NIPD using next generation sequencing technologies and NIPD using Methylation DNA Immunoprecipitation (MeDIP) with real time qPCR. Both approaches have been validated with blind studies and have >. 99% accuracy. NIPD using next generation sequencing is achieved by high throughput shotgun sequencing of DNA from plasma of maternal women followed by ratio comparisons of each chromosome sequence tag density over the median tag density of all autosomes (z-score analysis). The MeDIP real time qPCR method, which is described in this review in more detail, is based on the identification of differentially methylated regions (DMRs) and their use in discriminating normal from abnormal cases. More than 10,000 DMRs were identified for chromosomes 13, 18, 21, X and Y using high resolution oligo-arrays that can be potentially used for the NIPD of aneuploidies for chromosomes 13, 18, 21, X and Y. Both NIPD methods have several advantages and limitations and it is believed that they will soon be implemented in clinical practice. With the continuous advancements of genetic methodologies and technologies, we predict that within the next 10. years we will be able to provide NIPD for all common and rare genetic disorders where the molecular basis is known. © 2012 Elsevier B.V.

Papathanasiou E.S.,The Cyprus Institute of Neurology and Genetics | Zamba-Papanicolaou E.,The Cyprus Institute of Neurology and Genetics
Clinical Neurophysiology | Year: 2012

Objective: To compare disposable and reusable single fiber needle recordings in relation to stimulated single fiber studies. Methods: At least 10 potentials were sampled using each needle type from each patient with a minimum of 20 sampled potentials per patient. For successive patients either a disposable or reusable electrode was used first to remove effects of adaptation or fatigue. Results: Eighteen patients were prospectively recruited. No significant difference was found between disposable and reusable needle use with respect to mean consecutive difference with mean values (± standard deviation) of 25.29 ± 18.56 and 23.64 ± 16.80, respectively (p> 0.05). With regards to amplitude there was a significant difference between the two types with the biggest potentials recorded with disposable (339.85 ± 236.45) compared to reusable needles (248.23 ± 196.43) (p< 0.001). More potentials were obtained with disposable (2.73 ± 1.29) compared to reusable needles (2.33 ± 1.11) per acquisition run with the difference being statistically significant (0.01 < p< 0.05). Conclusions: Disposable single fibre needle electrodes obtained MCD values were comparable to those obtained with reusable single fibre needle electrodes but the amplitudes of the potentials were higher. The greater number of potentials obtained per acquisition run means that the examination can be performed quicker. Significance: Disposable single fiber needle use avoids the risk of prion infections and performs better than reusable needles. © 2011 International Federation of Clinical Neurophysiology.

Kleopa K.A.,The Cyprus Institute of Neurology and Genetics
Current Neuropharmacology | Year: 2011

Ion channels are complex transmembrane proteins that orchestrate the electrical signals necessary for normal function of excitable tissues, including the central nervous system, peripheral nerve, and both skeletal and cardiac muscle. Progress in molecular biology has allowed cloning and expression of genes that encode channel proteins, while compara- ble advances in biophysics, including patch-clamp electrophysiology and related techniques, have made the functional assessment of expressed proteins at the level of single channel molecules possible. The role of ion channel defects in the pathogenesis of numerous disorders has become increasingly apparent over the last two decades. Neurological channelo- pathies are frequently genetically determined but may also be acquired through autoimmune mechanisms. All of these autoimmune conditions can arise as paraneoplastic syndromes or independent from malignancies. The pathogenicity of autoantibodies to ion channels has been demonstrated in most of these conditions, and patients may respond well to immunotherapies that reduce the levels of the pathogenic autoantibodies. Autoimmune channelopathies may have a good prognosis, especially if diagnosed and treated early, and if they are non-paraneoplastic. This review focuses on clinical, pathophysiologic and therapeutic aspects of autoimmune ion channel disorders of the nervous system. © 2011 Bentham Science Publishers.

Mastroyiannopoulos N.P.,The Cyprus Institute of Neurology and Genetics | Nicolaou P.,The Cyprus Institute of Neurology and Genetics | Anayasa M.,The Cyprus Institute of Neurology and Genetics | Uney J.B.,University of Bristol | Phylactou L.A.,The Cyprus Institute of Neurology and Genetics
PLoS ONE | Year: 2012

Certain higher vertebrates developed the ability to reverse muscle cell differentiation (dedifferentiation) as an additional mechanism to regenerate muscle. Mammals, on the other hand, show limited ability to reverse muscle cell differentiation. Myogenic Regulatory Factors (MRFs), MyoD, myogenin, Myf5 and Myf6 are basic-helix-loop-helix (bHLH) transcription factors essential towards the regulation of myogenesis. Our current interest is to investigate whether down-regulation of MRFs in terminally differentiated mouse myotubes can induce reversal of muscle cell differentiation. Results from this work showed that reduction of myogenin levels in terminally differentiated mouse myotubes can reverse their differentiation state. Down-regulation of myogenin in terminally differentiated mouse myotubes induces cellular cleavage into mononucleated cells and cell cycle re-entry, as shown by re-initiation of DNA synthesis and increased cyclin D1 and cyclin E2 levels. Finally, we provide evidence that down-regulation of myogenin causes cell cycle re-entry (via down-regulation of MyoD) and cellularisation through separate pathways. These data reveal the important role of myogenin in maintaining terminal muscle cell differentiation and point to a novel mechanism by which muscle cells could be re-activated through its down-regulation. © 2012 Mastroyiannopoulos et al.

Inzelberg R.,The Sagol Neuroscience Center | Polyniki A.,The Cyprus Institute of Neurology and Genetics
Journal of the Neurological Sciences | Year: 2010

The occurrence of dementia in genetic Parkinson's disease is heterogeneous. The onset and progression of diverse forms of familial Parkinson's disease might be different than that of sporadic disease. Since dementia is an age related process, its risk increases with advanced disease severity and duration. The onset and progression of dementia is expected to vary between genetic forms, which present at diverse ages with different symptomatologies. It seems that genetic Parkinson's disease variants in which Lewy bodies are the prominent pathological hallmark - such as in PARK1, PARK4 and PARK8 - dementia is part of the phenotype. On the contrary, in PARK2 which is not accompanied by Lewy body accumulation, patients do not show a systematic cognitive decline. This review presents information on dementia in genetic forms of Parkinson's disease. © 2009 Elsevier B.V. All rights reserved.

Neocleous V.,The Cyprus Institute of Neurology and Genetics
Georgian medical news | Year: 2012

Congenital adrenal hyperplasia (CAH) is a common autosomal recessive disorder primarily caused by mutants in the CYP21A2 gene. Heterozygosity for CYP21A2 mutations in females increases their risk of clinically manifesting hyperandrogenism and the present study was designed to seek evidence on the prevalence and consequences of heterozygous CYP21A2 mutations in children with premature adrenarche and adolescents with hyperandrogenemia. The hormonal response to ACTH was evaluated in 17 girls with clinical signs of premature adrenarche and 17 adolescent females with hyperandrogenemia, along with direct DNA sequencing and MLPA analysis for mutations in the CYP21A2 gene. The suspicion of heterozygote state was based on the median plasma 17-OHP before and 60 minutes after ACTH stimulation. All 34 patients were identified as carriers of CYP21A2 mutations. The most frequent mutations among this cohort of carriers were the mild p.V281L (52.9%), followed by p.Q318stop (20.6%), p.V304M (8.9%), p.P482S (5.9%), p.P453S (5.9%), large deletion/conversion exons 1-4 (2.9%) and large deletion/conversion exons 6-8 (2.9%). Higher values of stimulated 17-OHP levels were found in the carriers of the p.V281L mutation compared with carriers of other mutations (mean=21.9 nmol/L vs 17.0 nmol/L). This finding supports the already identified notion that carriers of the mild p.V281L are at higher risk for hyperandrogenism than carriers of severe mutations. a. Females with premature adrenarche and hyperandrogenemia are likely to bear heterozygous CYP21A2 mutations, therefore systematic evaluation of 17-OHP values in combination with the molecular testing of CYP21A2 gene is beneficial, b. carriers of the mild p.V281L, are at higher risk of androgen excess compared to carriers of other types of mutations.

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