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1.
Artigo em Russo | MEDLINE | ID: mdl-38334732

RESUMO

OBJECTIVE: To study 11C-methionine (MET) metabolism in gliomas using CNS tumor biobank imaging data. MATERIAL AND METHODS: MRI and 11C-MET PET/CT were performed in 225 patients (49±14 years, M/F=84/101) according to standard protocols with analysis of 11C-MET accumulation index and volumetric parameters (V_FLAIR, V_PET and V_PET/FLAIR). These results were compared with molecular genetic testing and 2-year overall survival. RESULTS: We examined 225 patients with gliomas (97 glioblastomas, 70 astrocytomas, 58 oligodendrogliomas). Accumulation index and volume of 11C-MET in glioblastomas were significantly higher in the general group (AI=2.90, Se 69%, Sp 76%, AUC 0.76; V_PET=24.3 cm3, Se 67%, Sp 60%, AUC 0.65; V_PET/FLAIR 0.46, Se 60%, Sp 69%, AUC 0.67) and within the group of astrocytomas (AI=2.93, Se 68%, Sp 89%, AUC 0.84; V_PET=8.06 cm3, Se 91%, Sp 35%, AUC 0.66; V_PET/FLAIR 0.27, Se 77%, Sp 60%, AUC 0.71). The median 2-year overall survival in patients with glioblastomas was 13 months that was significantly lower compared to IDH «+¼ gliomas (p<0.0001). There was a relationship between high accumulation index of 11C-MET and shorter overall survival in patients with glioblastomas. Significantly higher AI >3.59 (Se 89%, Sp 67%, AUC 0.79) was additionally obtained in subgroup of patients with glioblastomas >50 years (n=34) for EGFR «+¼ tumors. CONCLUSION: We found variable 11C-MET metabolism in WHO 2021 gliomas and confirmed significant difference in metabolic activity and volume of 11C-MET accumulation in glioblastomas compared to IDH «+¼ gliomas. Moreover, we revealed the relationship between high accumulation index and shorter survival. Analysis of 11C-MET metabolism in patients over 50 years old revealed higher accumulation index in the EGFR «+¼ group. Further comparison of these imaging methods and assessment of other significant mutations are necessary to identify the anatomical and metabolic patterns of IDH «+¼ gliomas.


Assuntos
Astrocitoma , Neoplasias Encefálicas , Glioblastoma , Glioma , Humanos , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/genética , Tomografia por Emissão de Pósitrons/métodos , Radioisótopos de Carbono , Glioma/diagnóstico por imagem , Glioma/genética , Encéfalo/patologia , Metionina , Receptores ErbB
2.
Artigo em Inglês, Russo | MEDLINE | ID: mdl-37650276

RESUMO

Anaplastic astrocytoma (AA) is a rare intracerebral tumor. Therefore, the number of studies devoted to risk factors of overall and disease-free survival is small. This single-center clinical study is devoted to various factors influencing prognosis of treatment in this group of patients. MATERIAL AND METHODS: A retrospective study included 389 patients diagnosed with grade 3 astrocytoma. We analyzed dependence of overall and disease-free survival from the following factors: gender, age of onset of disease, tumor extent, surgery, neurological disorders before and after surgery (NANO grading system), Ki67 index, postoperative radio- and chemotherapy (number courses, treatment regimens). RESULTS: Significant risk factors for overall and disease-free survival were spread and volume of tumor, postoperative neurological aggravation, Ki67 index, IDH mutation, radio- and chemotherapy. Age, frontal lobe tumor and disease manifestation variant were significant only for overall, but not for disease-free survival. CONCLUSION: This study was based on material of one of the largest clinical series of patients with AA operated on in one center in «molecular¼ era. Our results are consistent with previous data. Analysis of tumor biology and risk factors for IDH-negative AA without molecular signs of glioblastoma may be perspective.


Assuntos
Astrocitoma , Humanos , Intervalo Livre de Doença , Antígeno Ki-67 , Estudos Retrospectivos , Astrocitoma/terapia , Prognóstico , Organização Mundial da Saúde
3.
Adv Gerontol ; 35(2): 255-262, 2022.
Artigo em Russo | MEDLINE | ID: mdl-35727932

RESUMO

The article presents the results of treatment of elderly and senile patients with complications of colon cancer, in whose perioperative management a multidisciplinary approach was used. The peculiarity of patients in older age groups, caused by polymorbidity, the phenomenon of mutual complication, requires the use of a non-standard approach in the treatment of complicated colon cancer, since the latter is accompanied by negative results. A comparative analysis of the results of treatment of 289 elderly and senile patients with complicated colon cancer by the traditional method and using a multidisciplinary approach was carried out. The patients were divided into two groups: study and control. In addition to the introduction of the principles of a multidisciplinary approach, additional diagnostic methods were used in the main group in order to more specifically determine the type, severity of complications, staging of the window process and determine functional operability. Patients of the main group, taking into account the implementation of a multidisciplinary approach, were operated using endovideosurgical technologies. In the group of patients where a multidisciplinary approach was used using additional diagnostic methods and minimally invasive treatment methods, a more favorable course of the postoperative period was noted with a decrease in postoperative complications (from 44,9 to 27,8%) and mortality (from 8,9 to 5,3%).


Assuntos
Neoplasias do Colo , Idoso , Neoplasias do Colo/complicações , Neoplasias do Colo/diagnóstico , Neoplasias do Colo/epidemiologia , Humanos , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia
4.
Artigo em Russo | MEDLINE | ID: mdl-35412712

RESUMO

Anaplastic pleomorphic xanthoastrocytoma is a rare tumor. There are still no objective data on the incidence of its diagnosis. OBJECTIVE: To study neuroimaging, morphological features of tumors, as well as factors affecting treatment and prognosis. MATERIAL AND METHODS: A retrospective study enrolled 42 patients operated on at the Burdenko Neurosurgery Center between 2003 and 2020. MR characteristics of anaplastic pleomorphic xanthoastrocytoma were analyzed. All patients underwent resection of tumor (total resection in 83.3% of cases). Redo surgeries were performed in 1/3 of patients. Mutational status of BRAF V600E was assessed in all patients. Adjuvant radio- and chemotherapy was performed in more than 80% of cases. Tyrosine kinase inhibitors were administered in 19% of cases. The follow-up period was 152 months (median 34 months). RESULTS: We found no pathognomonic MR signs of this disease. Indeed, anaplastic pleomorphic xanthoastrocytoma have the same signal characteristics as other malignant gliomas. The BRAF V600E mutation status was positive in 54.8% of cases. None patient had IDH-1 mutation. Mean Ki-67 index was 12.5%. The overall survival was 79 months (range 4-152). Seven (17%) patients are alive for more than 90 months. Only Ki-67 index and BRAF mutation significantly influenced the treatment prognosis and overall survival regardless the use of tyrosine kinase inhibitors. CONCLUSION: Such well-known factors for malignant glioma as patient age, total resection and adjuvant therapy did not significantly affect overall survival. Perhaps, searching for new molecular genetic features will reveal additional significant factors of prognosis in patients with anaplastic pleomorphic xanthoastrocytoma.


Assuntos
Astrocitoma , Neoplasias Encefálicas , Glioma , Astrocitoma/diagnóstico por imagem , Astrocitoma/genética , Astrocitoma/terapia , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Humanos , Antígeno Ki-67 , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/genética , Estudos Retrospectivos
5.
Artigo em Inglês, Russo | MEDLINE | ID: mdl-36252190

RESUMO

OBJECTIVE: To study the effect of TERT mutation on overall and relapse-free survival in patients with IDH-negative diffuse astrocytomas grade III (anaplastic gliomas). MATERIAL AND METHODS: The study included 45 patients aged 45.5 years. Forty-two patients underwent resection of tumor, other 3 ones - stereotactic biopsy. TERT mutation was identified in 21 patients. External beam radiation therapy was performed in 35 patients (60 Gy), chemotherapy - in 34 patients (mainly temozolomide). Follow-up data were available in 44 patients. RESULTS: Median of overall survival in patients with TERT mutation was 15.3 months, in patients with TERT-negative tumors - 65.1 months. Median of relapse-free survival in patients with TERT-positive anaplastic astrocytoma (AA) was 13.3 months, in patients with TERT-negative glioma - 57.7 months. These differences were not significant. Relapse-free survival was higher in patients with AA and no TERT mutation at all intervals, but especially at early stages (12 and 24 months). CONCLUSION: Inclusion of TERT mutation in mandatory examination panel for gliomas in general and, in particular, gliomas grade II/III without IDH mutation can lead to sub-classification of these tumors in the near future. Routine analysis of TERT mutation in these patients will be valuable for correct medical consultation regarding prognosis and adequate adjuvant treatment.


Assuntos
Astrocitoma , Neoplasias Encefálicas , Glioblastoma , Glioma , Telomerase , Humanos , Astrocitoma/diagnóstico , Astrocitoma/genética , Astrocitoma/terapia , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Glioblastoma/diagnóstico , Glioblastoma/genética , Glioblastoma/terapia , Glioma/diagnóstico , Glioma/genética , Glioma/terapia , Isocitrato Desidrogenase/genética , Mutação , Prognóstico , Telomerase/genética , Temozolomida/uso terapêutico , Pessoa de Meia-Idade
6.
Adv Gerontol ; 34(2): 277-286, 2021.
Artigo em Russo | MEDLINE | ID: mdl-34245512

RESUMO

The most common treatment for menopausal syndrome is menopausal hormone therapy (MHT), however, the safety of MHT, due to the risk of developing and recurrent breast cancer (BC), is still a matter of debate. The review presents the results of randomized cohort studies of this issue. It has been shown that MHT increases the risk of developing of breast cancer and disease recurrence after treatment. Risk of breast cancer developing in women getting MHT, depends on body mass index (BMI), duration of hormone use and dose of drugs, and is greater in thin women comparing with women with increased BMI, and also greater in estrogen-progestin combined MHT users comparing with estrogen-only users. It was found that in women using MHT hormone-dependent forms of cancer developed more often, but by the time of diagnosis, disease was found in more advanced stage and metastases in lymph nodes were found more often comparing with patients who did not use MHT. Risk of breast cancer recurrence is less with the use of low doses of vaginal estrogen. An alternative option for the relief of menopausal disorders in breast cancer patients during and after treatment is using of pineal gland hormone melatonin, since, along with its anti-aging properties, it is able to suppress cancer at the stages of initiation, progression and metastasis and has the ability to reduce the toxic effects of anticancer drugs while increasing their effectiveness.


Assuntos
Neoplasias da Mama , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/epidemiologia , Terapia de Reposição de Estrogênios/efeitos adversos , Estrogênios/efeitos adversos , Feminino , Humanos , Menopausa , Recidiva Local de Neoplasia
7.
Artigo em Russo | MEDLINE | ID: mdl-34463456

RESUMO

This review is devoted to the problem of anaplastic cerebral gliomas. The authors consider classification, neuroimaging of these tumors including comparison of magnetic resonance imaging and positron emission tomography data. Clinical manifestations of anaplastic gliomas, issues of their histological and molecular genetic classification are discussed. Moreover, the authors compare the data of neuroimaging and genetic examinations of tumors. Other issues are multicomponent treatment and prognosis in patients with anaplastic glioma of the brain.


Assuntos
Astrocitoma , Neoplasias Encefálicas , Glioblastoma , Oligodendroglioma , Astrocitoma/diagnóstico por imagem , Encéfalo , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/genética , Humanos , Oligodendroglioma/diagnóstico por imagem , Oligodendroglioma/genética
8.
Phys Rev Lett ; 125(26): 262301, 2020 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-33449792

RESUMO

Flow coefficients v_{n} of the orders n=1-6 are measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI for protons, deuterons, and tritons as a function of centrality, transverse momentum, and rapidity in Au+Au collisions at sqrt[s_{NN}]=2.4 GeV. Combining the information from the flow coefficients of all orders allows us to construct for the first time, at collision energies of a few GeV, a multidifferential picture of the angular emission pattern of these particles. It reflects the complicated interplay between the effect of the central fireball pressure on the emission of particles and their subsequent interaction with spectator matter. The high precision information on higher order flow coefficients is a major step forward in constraining the equation of state of dense baryonic matter.

9.
Adv Gerontol ; 33(2): 228-239, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32593236

RESUMO

The completely formed database of the Population Cancer Registry (PCR database) of the North-Western Federal district of the Russian Federation in February 2019 has significantly expanded the ability to objectively assess the activities of the cancer service on a more reliable basis of analytical materials. In Russia, for the first time, it was possible to conduct epidemiological studies of malignant tumors for rare tumor locations, any age groups, and calculations of patient survival rates. The PCR database has more than 1 million observations and includes all the headings and subheadings of ICD-10 for class II - codes C00-96. The article will present the dynamics of morbidity and mortality of the population of the northwestern Federal district of the Russian Federation in comparison with the national average, the reliability of accounting and survival of patients with malignant tumors. For 8 years, the growth of cancer incidence in the Northwestern Federal district of the Russian Federation by 10,4% in standardized indicators and a decrease in population mortality in the Northwestern Federal district of the Russian Federation by 11,4% in the same indicators. The dynamics of the 5-year observed survival rate of patients with Northwestern Federal district of the Russian Federation, taking into account age groups, is calculated. The reliability of the PCR database of the Northwestern Federal district of the Russian Federation is confirmed by the fact that the materials of 3 administrative territories are included in the IARC monograph «Cancer incidence in five continents. Vol. XI¼ (Saint-Petersburg, Arkhangelsk region and the Republic of Karelia).


Assuntos
Neoplasias/epidemiologia , Sistema de Registros , Bases de Dados Factuais , Humanos , Morbidade , Neoplasias/mortalidade , Reprodutibilidade dos Testes , Federação Russa/epidemiologia , Taxa de Sobrevida
10.
Adv Gerontol ; 33(1): 65-73, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32362086

RESUMO

Modern approaches to the organization of diagnosis and treatment of elderly and senile patients with malignant tumors allow to maintain the necessary level of health, improve the quality of life and increase life expectancy. Assessment of geriatric status in Oncology allows: to predict complications during the complex treatment, including drug treatment; to modify treatment to reduce the risk factors of adverse outcomes; to select patients for specialized treatment using standard schemes. So, timely assessment of geriatric syndromes and their correction can expand the indications for specialized treatment of elderly and senile patients.


Assuntos
Avaliação Geriátrica , Oncologia , Neoplasias/terapia , Idoso , Humanos , Qualidade de Vida
11.
Phys Rev Lett ; 123(2): 022002, 2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31386541

RESUMO

We present the first observation of K^{-} and ϕ absorption within nuclear matter by means of π^{-}-induced reactions on C and W targets at an incident beam momentum of 1.7 GeV/c studied with HADES at SIS18/GSI. The double ratio (K^{-}/K^{+})_{W}/(K^{-}/K^{+})_{C} is found to be 0.319±0.009(stat)_{-0.012}^{+0.014}(syst) indicating a larger absorption of K^{-} in heavier targets as compared to lighter ones. The measured ϕ/K^{-} ratios in π^{-}+C and π^{-}+W reactions within the HADES acceptance are found to be equal to 0.55±0.04(stat)_{-0.07}^{+0.06}(syst) and to 0.63±0.06(stat)_{-0.11}^{+0.11}(syst), respectively. The similar ratios measured in the two different reactions demonstrate for the first time experimentally that the dynamics of the ϕ meson in nuclear medium is strongly coupled to the K^{-} dynamics. The large difference in the ϕ production off C and W nuclei is discussed in terms of a strong ϕN in-medium coupling. These results are relevant for the description of heavy-ion collisions and the structure of neutron stars.

12.
J Chem Phys ; 150(6): 064312, 2019 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-30770013

RESUMO

Potential energy functions of the OH molecule are investigated from small to large inter-atomic distances R. The electronic problem is treated using an efficient Full Configuration Interaction (Full CI) approach that avoids orbital jumps found usually in multi-configuration self-consistent-field followed by multi-reference configuration interaction calculations of excited states. The calculations are performed for all the doublet, quartet, and sextet OH molecular states, up to the O(2p34s 3S) + H(1s 2S) asymptote, and for the lowest O- + H+ and O+ + H- ionic states. Inter-atomic distances, ranging from 0.5 Å to 20 Å, are spanned with a very small step in order to describe accurately the avoided crossings between the adiabatic potential energy functions. The accuracy of the potentials at small and large R values is analyzed. These Full CI calculations provide for the first time a global description of the 40 lowest molecular states of OH, well suited for dynamical calculations. The resulting potentials are used to obtain first estimates of cross sections and rate coefficients for different inelastic processes through the multichannel approach. This method, based on a Landau-Zener formalism taking into account the ionic-covalent avoided crossings at large distances, gives reliable results for the most intense transitions. It is shown that the largest rate coefficients correspond to mutual neutralization and ion-pair production processes.

13.
Urologiia ; (6): 150-155, 2019 12 31.
Artigo em Russo | MEDLINE | ID: mdl-32003187

RESUMO

Delayed ejaculation is a form of sexual disorders, which is characterized by constant or intermittent delays or absence of ejaculation and orgasm, despite normal sexual arousal and erectile function. Delayed ejaculation is one of the most studied and rare types of male sexual dysfunctions, which leads to depression, anxiety, and often is a reason of low self-esteem, reduced satisfaction of a man with his partner, and worsening of relationships between partners. In some cases, delayed ejaculation and anejaculation cause infertility. Current views on epidemiology, diagnostics and treatment strategy of delayed ejaculation are presented in the article.


Assuntos
Disfunções Sexuais Fisiológicas , Disfunções Sexuais Psicogênicas , Ejaculação , Humanos , Masculino , Orgasmo , Disfunções Sexuais Fisiológicas/diagnóstico , Disfunções Sexuais Fisiológicas/etiologia , Disfunções Sexuais Fisiológicas/terapia , Disfunções Sexuais Psicogênicas/diagnóstico , Disfunções Sexuais Psicogênicas/etiologia , Disfunções Sexuais Psicogênicas/terapia
14.
Artigo em Russo | MEDLINE | ID: mdl-31577268

RESUMO

The possibility of segmenting three-dimensional objects by DICOM-series is well known and available both on specialized workstations and on personal computers. The technique, however, is relatively rarely used in clinical practice, and we believe that the benefits of preoperative preparation using segmented 3D models are underestimated. The article is devoted to our experience in using segmentation of anatomical structures based on CT and MRI for preoperative preparation for surgical operations performed in neurosurgical departments on patients with vascular pathology. The paper discusses the types and possibilities of segmentation, provides some examples describing the clinical use of the technique.


Assuntos
Encéfalo , Modelos Anatômicos , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Humanos , Imageamento por Ressonância Magnética
15.
Clin Genet ; 93(5): 1015-1021, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29406563

RESUMO

Distribution of cancer-predisposing mutations demonstrates significant interethnic variations. This study aimed to evaluate patterns of APC and MUTYH germ-line mutations in Russian patients with colorectal malignancies. APC gene defects were identified in 26/38 (68%) subjects with colon polyposis; 8/26 (31%) APC mutations were associated with 2 known mutational hotspots (p.E1309Dfs*4 [n = 5] and p.Q1062fs* [n = 3]), while 6/26 (23%) mutations were novel (p.K73Nfs*6, p.S254Hfs*12, p.S1072Kfs*9, p.E1547Kfs*11, p.L1564X and p.C1263Wfs*22). Biallelic mutations in MUTYH gene were detected in 3/12 (25%) remaining subjects with polyposis and in 6/90 (6.7%) patients with colorectal cancer (CRC) carrying KRAS p.G12C substitution, but not in 231 early-onset CRC cases negative for KRAS p.G12C allele. In addition to known European founder alleles p.Y179C and p.G396D, this study revealed a recurrent character of MUTYH p.R245H germ-line mutation. Besides that, 3 novel pathogenic MUTYH alleles (p.L111P, p.R245S and p.Q293X) were found. Targeted next-generation sequencing of 7 APC/MUTYH mutation-negative DNA samples identified novel potentially pathogenic POLD1 variant (p.L460R) in 1 patient and known low-penetrant cancer-associated allele CHEK2 p.I157T in 3 patients. The analysis of 1120 healthy subjects revealed 15 heterozygous carriers of recurrent MUTYH mutations, thus the expected incidence of MUTYH-associated polyposis in Russia is likely to be 1:23 000.


Assuntos
Proteína da Polipose Adenomatosa do Colo/genética , Neoplasias Colorretais/genética , DNA Glicosilases/genética , Predisposição Genética para Doença , Adulto , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/patologia , Análise Mutacional de DNA , Feminino , Genótipo , Mutação em Linhagem Germinativa/genética , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Fenótipo , Federação Russa/epidemiologia
16.
Bull Exp Biol Med ; 165(1): 22-26, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29797129

RESUMO

Blood plasma proteome in patients with cerebral ischemia and healthy individuals was studied using comparative proteomic analysis based on tandem HPLC-MS/MS. Mass spectra were analysed in an automated mode using Progenesis LS-MS software and 256 proteins were identified. Significant quantitative differences were revealed for 20 proteins. It was found that changes in the blood plasma proteome in subjects with cerebral ischemia involved a wide range of proteins: molecular chaperones, fibrinolysis, angiogenesis, and immune system proteins, proteins involved in homeostasis maintenance, cell differentiation and proliferation, regulators of apoptosis, and cytoskeleton proteins.


Assuntos
Isquemia Encefálica/sangue , Infarto Cerebral/sangue , Idoso , Proteínas Sanguíneas/análise , Cromatografia Líquida/métodos , Feminino , Humanos , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Proteoma/análise
17.
Nanotechnology ; 28(13): 135204, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28151731

RESUMO

We studied space-charge-distribution phenomena in planar GaN nanowires and nanoribbons (NRs). The results obtained at low voltages demonstrate that the electron concentration changes not only at the edges of the NR, but also in the middle part of the NR. The effect is stronger with decreasing NR width. Moreover, the spatial separation of the positive and negative charges results in electric-field patterns outside the NR. This remarkable feature of electrostatic fields outside the NR may be even stronger in 2D material structures. For larger voltages the space-charge-limited current (SCLC) effect determines the main mechanism of transport in the NR samples. The onset of the SCLC effect clearly correlates with the NR width. The results are confirmed by noise spectroscopy studies of the NR transport. We found that the noise increases with decreasing NR width and the shape of the spectra changes with voltage increase with a tendency toward slope (3/2), reflecting diffusion processes due to the SCLC effect. At higher voltages noise decreases as a result of changes in the scattering mechanisms. We suggest that the features of the electric current and noise found in the NRs are of general character and will have an impact on the development of NR-based devices.

18.
J Chem Phys ; 146(1): 014304, 2017 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-28063454

RESUMO

The accurate highly correlated ab initio calculations for ten low lying covalent Σ+2 states of CaH molecule, and one ionic Ca+H- state, are performed using large active space and extended basis set, with special attention to the long-range (6-20 Å) region where a number of avoided crossings between ionic and covalent states occur. These states are further transformed to a diabatic representation using a numerical diabatization scheme based on the minimization of derivative coupling. This results in a smooth diabatic Hamiltonian which can be easily fit to an analytic form. The diagonal elements of the diabatic potentials were then empirically corrected to reproduce experimental dissociation energies. Though the emphasis is on the asymptotic region, the obtained spectroscopic constants are in good agreement with available experimental and theoretical data. The resulting analytical Hamiltonian, after back transformation to adiabatic representation, is used to obtain cross sections for different inelastic processes using both the multichannel and the branching probability current approaches. It is shown that while for most intense transitions both approaches provide very close results, the multichannel approach underestimates the cross sections of weak transitions, as a consequence of the short-range avoided crossings that are accounted for only in the branching probability current method.

19.
J Chem Phys ; 147(23): 234301, 2017 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-29272927

RESUMO

We employ the on-the-fly surface hopping classical trajectory algorithm to study the electron detachment process in low-energy H- + H2 collisions. The ground-state and the first-excited-state Local Complex Potentials (LCPs) calculated by the generalized diatomics-in-molecule method are used for the full three-dimensional nonadiabatic nuclear dynamics. Two kinds of nonadiabatic effects are taken into account: discrete-discrete transitions and discrete-continuous transitions. Discrete-discrete nonadiabatic transition probabilities are calculated by means of the adiabatic-potential-based formula within the Landau-Zener model for each individual trajectory computed along real parts of the LCPs. Discrete-continuous (electron detachment) nonadiabatic transition probabilities are calculated via quasi-stationary widths which are related to the imaginary parts of the LCPs of both the electronic states of the H3- anion. Two mechanisms of the electron detachment process are treated and discussed: the direct mechanism based on quasi-stationarity of the ground state and the indirect mechanism based on both nonadiabatic transitions from the ground state to the first excited state and quasi-stationarity of the excited state. It is shown that the direct mechanism prevails at low collision energies, while the indirect mechanism makes a substantial contribution at relatively high collision energies, roughly higher than 5 eV. At collision energies higher than 2 eV, the electron detachment probability has rather high values and this affects noticeably other inelastic processes in these collisions. The electron detachment cross section in H- + H2 collisions is calculated for the collision energy range from 1 to 100 eV and a reasonable agreement with available experimental data is obtained.

20.
Artigo em Russo | MEDLINE | ID: mdl-28665384

RESUMO

The median overall survival of glioblastoma patients is about 15 months. Only a small number of patients survive 3 years. The factors of a favorable prognosis for the 'longevity phenomenon' in glioblastoma patients are not fully understood. OBJECTIVE: to determine the occurrence rate of long-living patients with glioblastomas, identify clinical predictors of a favorable prognosis, and identify the presence and prognostic significance of an IDH1 mutation. MATERIAL AND METHODS: Among 1494 patients operated on for glioblastoma at the Burdenko Neurosurgical Institute from 2007 to 2012, there were 84 (5.6%) patients who lived more than 3 years after primary surgery. In all the cases, histological specimens were reviewed, and immunohistochemical detection of a mutant IDH1 protein was performed. Overall survival was calculated from the time of first surgery to the date of the last consultation or death, and the recurrence-free period was calculated from the time of first surgery to MRI-verified tumor progression. RESULTS: The median age of long-living patients with glioblastoma was 45 years (19-65 years). All tumors were located supratentorially. The median Karnofsky performance status score at the time of surgery was 80 (range, 70-100). All patients underwent microsurgical resection of the tumor, followed by chemoradiotherapy. The median recurrence-free period was 36 months (5-98 months). Overall survival of 48, 60, and 84 months was achieved in 23, 15 and 6% of patients, respectively. Among 49 specimens available for the IDH1 analysis, 14 (28.6%) specimens had a mutant protein. There was no significant difference in survival rates in patients with positive and negative results for IDH1 (44.1 vs. 40.8 months; p>0.05). CONCLUSION: The significance of various factors that may be predictors of a favorable course of the disease is discussed in the literature. This work is the first part of analysis of prognostically significant factors positively affecting overall survival of glioblastoma patients. In our series, the predictors of a favorable prognosis for long-living patients with the verified diagnosis of glioblastoma were as follows: young age, the supratentorial location of the tumor, a high Karnofsky score before surgery, and tumor resection. In our series, we used immunohistochemical tests and found no prognostic significance of the IDH1 gene mutation; further analysis will require application of direct sequencing. We plan to study other morphological and molecular genetic features of tumors, which explain prolonged survival of glioblastoma patients, as well as the role of various types of combined chemoradiation treatment.


Assuntos
Neoplasias Encefálicas/mortalidade , Glioblastoma/mortalidade , Isocitrato Desidrogenase/genética , Adulto , Fatores Etários , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Intervalo Livre de Doença , Feminino , Glioblastoma/diagnóstico por imagem , Glioblastoma/genética , Glioblastoma/terapia , Humanos , Estimativa de Kaplan-Meier , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Mutação , Estudos Retrospectivos , Fatores de Tempo , Adulto Jovem
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