Publications by authors named "A G Melikyan"

49 Publications

Low V617F Allele Burden in Ph-Negative Chronic Myeloproliferative Neoplasms Is Associated with Additional or Gene Mutations.

Genes (Basel) 2021 Apr 12;12(4). Epub 2021 Apr 12.

National Research Center for Hematology, Novy Zykovski lane 4a, 125167 Moscow, Russia.

(Janus kinase 2) V617F, (Calreticulin) exon 9, and (receptor for thrombopoietin) exon 10 mutations are associated with the vast majority of Ph-negative chronic myeloproliferative neoplasms (MPNs). These mutations affect sequential stages of proliferative signal transduction and therefore, after the emergence of one type of mutation, other types should not have any selective advantages for clonal expansion. However, simultaneous findings of these mutations have been reported by different investigators in up to 10% of MPN cases. Our study includes DNA samples from 1958 patients with clinical evidence of MPN, admitted to the National Research Center for Hematology for genetic analysis between 2016 and 2019. In 315 of 1402 cases (22.6%), mutations were detected. In 23 of these 315 cases (7.3%), the JAK2 V617F mutation was found in addition to the mutation. In 16 from 24 (69.6%) cases, with combined and mutations, V617F allele burden was lower than 1%. A combination of V617F with W515L/K was also observed in 1 out of 1348 cases, only. allele burden in this case was also lower than 1%. Additional mutations may coexist over the low background of JAK2 V617F allele. Therefore, in cases of detecting MPNs with a low allelic load V617F, it may be advisable to search for other molecular markers, primarily mutations in exon 9 of . The load of the combined mutations measured at different time points may indicate that, at least in some cases, these mutations could be represented by different clones of malignant cells.
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http://dx.doi.org/10.3390/genes12040559DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8069892PMC
April 2021

[Stereoelectroencephalography (seeg): a brief historical review of modern deep electrode implantation methods used for diagnosis and treatment of epilepsy].

Zh Vopr Neirokhir Im N N Burdenko 2021 ;85(2):99-106

Burdenko Neurosurgical Center, Moscow, Russia.

More than 30% of patients with symptomatic epilepsy are resistant to drug therapy and therefore surgical treatment is the method of choice for such patients. Search and localization of the epileptogenic zone and all parts of the neural networks involved in stereotypic seizures are the most important objectives of pre-surgical evaluation and the prerequisite for the successful surgery. In the last decade, stereotactic implantation of multiple intracerebral multi-contact electrodes (SEEG) has been increasingly used for this purpose. The article includes a brief history of SEEG and a description of the major techniques for stereotactic implantation of electrodes. Information on accuracy (errors and deviations from planned target) and on complications are summarized. The data on the clinical value of the method and how these data affected the results of subsequent treatment are highlighted. The method of thermocoagulation and its results are briefly considered.
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http://dx.doi.org/10.17116/neiro20218502199DOI Listing
April 2021

[Influence of resection quality on postoperative outcomes in children with atypical teratoid-rhabdoid tumor of the central nervous system].

Zh Vopr Neirokhir Im N N Burdenko 2021 ;85(2):17-25

Voino-Yasenetsky Research and Practical Center for Specialized Medical Care, Moscow, Russia.

The purpose of this study was to assess the influence of resection quality on overall survival and disease-free survival in children with atypical teratoid-rhabdoid tumors (ATRT). The study included children younger than 18 years old for the period from 2008 to 2019. There were 134 interventions in 105 patients with ATRT including 11 redo resections («second-look» surgery) and 18 procedures for tumor recurrence. Age of patients ranged from 2 to 168 months (median 21 months). Patients with supratentorial tumors prevailed (50.5%), infratentorial neoplasms were diagnosed in 45.7% of patients, spinal cord lesion - 3.8% of cases. At the first stage, all patients underwent surgical treatment. Total resection was achieved in 34 (32.4%) patients, subtotal - 37 (35.2%) patients, partial resection - 30 (28.6%) patients. Biopsy was performed in 4 (3.8%) patients. Quality of resection and age at surgery significantly influenced overall and disease-free survival. Extended resection of tumor followed by adjuvant chemo- and radiotherapy are required to improve survival although ATRTs are high-grade neoplasms with poor prognosis.
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http://dx.doi.org/10.17116/neiro20218502117DOI Listing
April 2021

Experimental demonstration of a 4,294,967,296-QAM-based Y-00 quantum stream cipher template carrying 160-Gb/s 16-QAM signals.

Opt Express 2021 Feb;29(4):5658-5664

We demonstrate a 4,294,967,296-quadrature amplitude modulation (QAM) based Y-00 quantum stream cipher system carrying a 160-Gb/s 16-QAM signal transmitted over 320-km SSMF. The ultra-dense QAM cipher template is realized by an integrated two-segment silicon photonics I/Q modulator.
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http://dx.doi.org/10.1364/OE.405390DOI Listing
February 2021

[The prognostic value of ASXL1 mutation in primary myelofibrosis. Literature review and clinical case description].

Ter Arkh 2020 Sep 1;92(7):95-99. Epub 2020 Sep 1.

National Research Center for Hematology.

Primary myelofibrosis is a myeloproliferative neoplasm that occurs de novo, characterized by clonal proliferation of stem cells, abnormal expression of cytokines, bone marrow fibrosis, hepatosplenomegaly as a result of extramedullary hematopoiesis, symptoms of tumor intoxication, cachexemia, peripheral blood leukoerythroblastosis, leukemic progression and low survival. Primary myelofibrosis is a chronic incurable disease. The aims of therapy: preventing progression, increasing overall survival, improving quality of life. The choice of therapeutic tactics is limited. Allogenic hematopoietic stem cell transplantation is the only method that gives a chance for a cure. The role of mutations in a number of genes in the early identification of candidates for allogeneic hematopoietic stem cell transplantation is being actively studied. The article describes the clinical case of the detection ofASXL1gene mutations in a patient with prefibrous primary myelofibrosis. The diagnosis was established on the basis of WHO criteria 2016. The examination revealed a mutation ofASXL1. Interferon alfa therapy is carried out, against the background of which clinico-hematological remission has been achieved. Despite the identified mutation, the patient is not a candidate for allogeneic hematopoietic stem cell transplantation. Given the unfavorable prognostic value of theASXL1mutation, the patient is subject to active dynamic observation and aggressive therapeutic tactics when signs of disease progression appear.
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http://dx.doi.org/10.26442/00403660.2020.07.000788DOI Listing
September 2020