БЕЗОПАСНОСТЬ ИСПОЛЬЗОВАНИЯ РЕТРОВИРУСНЫХ ВЕКТОРОВ В ГЕННОЙ ТЕРАПИИ

Retroviral vectors are widely used in gene therapy and found to be an effective tool for the delivery of genetic constructs into cells. A unique feature of these vectors is the ability to incorporate therapeutic genes into a chromosome that ensures its passage to all progeny cells and enables to cure the diseases requiring genetic correction of dividing cells such as hematopoietic cells or skin cells. Retroviral vectors have been successfully used in gene therapy clinical trials for the treatment of 2 forms of severe combined immunodeficiencies and some other hereditary blood disorders. However, the integration of the vector into the chromosome was accompanied by genotoxicity and caused development of hematologic malignancies in several patients. Later it was shown that genotoxicity is not a general feature of retroviral vectors but it depends on many factors. In the present article we discuss safety issues concerning the use of different retroviral vectors in gene therapy. The description of modern vectors which designed to avoid the genotoxicity and other possible side effects are given. Ретровирусные векторы широко используют в генотерапевтических исследованиях, они признаны эффективным инструментом для доставки генетических конструкций в клетки. Уникальной особенностью данных векторов является способность эффективно встраивать терапевтические гены в хромосому, что обеспечивает передачу генов дочерним клеткам и позволяет лечить заболевания, требующие генетической коррекции активно делящихся клеток, таких как гемопоэтические клетки или клетки кожи. Ретровирусные векторы были успешно использованы в клинических испытаниях препаратов, направленных на лечение 2 форм тяжелых комбинированных иммунодефицитов и некоторых других врожденных заболеваний крови. Однако в нескольких случаях интеграция вектора в хромосому сопровождалась генотоксичностью и привела к развитию онкогематологического заболевания. В дальнейшем было показано, что генотоксичность не является неотъемлемой чертой всех ретровирусных векторов, а зависит от многих факторов. В настоящей статье рассматриваются вопросы безопасности применения различных ретровирусных векторов в генной терапии. Приведено описание современных векторов, обладающих свойствами, позволяющими избежать генотоксичности и других возможных побочных эффектов.

Theoretical-experimental model for predicting crack growth rate in structural alloys under combined action of fatigue and creep

Holding periods of 300 and 3600 s in a trapezoidal load cycle are shown to increase the crack growth rate dozens of times for alloy EP962 and several-fold for alloy EP742 at a temperature of 973 K. It is demonstrated that in the presence of the first portion on the creep crack growth diagram, whereon the crack growth rate decreases, the crack growth kinetics for a trapezoidal load cycle can be predicted using the hypothesis of the linear summation of fatigue and creep crack growth rates provided that the peculiarities of the first portion of the creep crack growth diagram are taken into account. Empirical approaches are proposed for determining the mean crack velocity in the first portion of the creep crack growth diagram.Установлено, что наличие участков выдерж­ки 300 и 3600 с в трапецевидном цикле нагружения при температуре 973 К приво­дит к повышению скорости роста трещины. Показано, что при наличии на диаграмме роста трещины ползучести первого участка, на котором наблюдается снижение скорости роста трещины, можно прогнозировать ки­нетику ее роста для трапецевидного цикла нагружения на основании гипотезы линей­ного суммирования скоростей трещин уста­лости и ползучести. При этом необходимо учитывать особенности первого участка диа­граммы роста трещин ползучести. Предложены эмпирические подходы к определению средней скорости роста трещины на первом участке диаграммы

Effects of nonlinear sweep in the Landau-Zener-Stueckelberg effect

We study the Landau-Zener-Stueckelberg (LZS) effect for a two-level system with a time-dependent nonlinear bias field (the sweep function) W(t). Our main concern is to investigate the influence of the nonlinearity of W(t) on the probability P to remain in the initial state. The dimensionless quantity epsilon = pi Delta ^2/(2 hbar v) depends on the coupling Delta of both levels and on the sweep rate v. For fast sweep rates, i.e., epsilon << l and monotonic, analytic sweep functions linearizable in the vicinity of the resonance we find the transition probability 1-P ~= epsilon (1+a), where a>0 is the correction to the LSZ result due to the nonlinearity of the sweep. Further increase of the sweep rate with nonlinearity fixed brings the system into the nonlinear-sweep regime characterized by 1-P ~= epsilon ^gamma with gamma neq 1 depending on the type of sweep function. In case of slow sweep rates, i.e., epsilon >>1 an interesting interference phenomenon occurs. For analytic W(t) the probability P=P_0 e^-eta is determined by the singularities of sqrt{Delta ^2+W^2(t)} in the upper complex plane of t. If W(t) is close to linear, there is only one singularity, that leads to the LZS result P=e^-epsilon with important corrections to the exponent due to nonlinearity. However, for, e.g., W(t) ~ t^3 there is a pair of singularities in the upper complex plane. Interference of their contributions leads to oscillations of the prefactor P_0 that depends on the sweep rate through epsilon and turns to zero at some epsilon. Measurements of the oscillation period and of the exponential factor would allow to determine Delta, independently.Comment: 11 PR pages, 12 figures. To be published in PR

The role of plasmacytoid dendritic cells as a new immune cells in the pathogenesis of chronic hepatitis C, chronic hepatitis B and HIV

The objective. To establish the nature and degree of participation of plasmacytoid dendritic cells (pDCs) in the immunogenesis of chronic hepatitis C, hepatitis b and HIV infection, by comparative determination of the number and functional activity of pDCs in these infections. Patients and methods. We examined 123 persons. 62 patients of them with chronic hepatitis C, 21 with chronic hepatitis B, 28 HIV patients and 12 healthy individuals. The pDC number was enumerated by flow cytometry. In vitro IFN production in the whole blood in response to pDC-specific stimulus unmethylated CpG oligonucleotides was determined by ELISA. Results. It was found that the percentage and absolute number of pDCs of all patients was below the same indicators of healthy individuals (p < 0.05). In the CHC patients as an absolute (8.3 ± 0.7) and relative (0.2 ± 0.015) pDCs content was significantly higher than in hepatitis B (4,3 ± 0.7 and 0.11 ± 0.02) (p < 0.0001 and p = 0.002 respectively) and HIV patients (5.25 ± 0.7 and 0.13 ± 0.015); (p = 0.003 and p = 0.003). Production of IFN pDCs was higher in HCV and chronic hepatitis B patients against the indicators of healthy individuals. However, we have not established reliable differences between the quantitative content of pDCs in patients with hepatitis B and HIV-infected patients (p = 0.35 and p = 0.5 respectively), which may play a crucial role in the escape mechanisms of these infections from the action of the immune system. A particularly important role in the pathogenesis of these infections plays the functional state of pDCs. Shown stimulation of IFN production of pDCs in response to viral infection in patients with CHC and CHB vs index in healthy individuals. While patients with CHC production of IFN is significantly higher (203.7 ± 54.4) than in chronic hepatitis B (7.9 ± 1.9; p = 0.007), whereas in patients with HIV infection it is not detected and does not differ from that in healthy individuals. Conclusion. It is shown that the characteristics of the state of pDCs with infectious diseases of various etiologies have significant differences. The reduction of the content of pDCs compared with healthy individuals noted in chronic infections, however, the level of decrease depends on the etiology of the pathogen and stage of the disease. In such infectious diseases as viral hepatitis B and HIV infection there quantitative defect was marked in this cell population. Functional activity (interferonogenesis) in pDCs is maximally expressed when HCV is less significant with CHB, whereas in HIV-infected patients in General, paralyzed and does not differ from that of healthy people. These data demonstrate the close relationship activities of plasmacytoid dendritic cells with the pathogenesis and course of the studied infections, it is important to find new approaches to their treatment

The role of plasmacytoid dendritic cells as a new immune cells in the pathogenesis of chronic hepatitis C, chronic hepatitis B and HIV

The objective. To establish the nature and degree of participation of plasmacytoid dendritic cells (pDCs) in the immunogenesis of chronic hepatitis C, hepatitis b and HIV infection, by comparative determination of the number and functional activity of pDCs in these infections. Patients and methods. We examined 123 persons. 62 patients of them with chronic hepatitis C, 21 with chronic hepatitis B, 28 HIV patients and 12 healthy individuals. The pDC number was enumerated by flow cytometry. In vitro IFN production in the whole blood in response to pDC-specific stimulus unmethylated CpG oligonucleotides was determined by ELISA. Results. It was found that the percentage and absolute number of pDCs of all patients was below the same indicators of healthy individuals (p < 0.05). In the CHC patients as an absolute (8.3 ± 0.7) and relative (0.2 ± 0.015) pDCs content was significantly higher than in hepatitis B (4,3 ± 0.7 and 0.11 ± 0.02) (p < 0.0001 and p = 0.002 respectively) and HIV patients (5.25 ± 0.7 and 0.13 ± 0.015); (p = 0.003 and p = 0.003). Production of IFN pDCs was higher in HCV and chronic hepatitis B patients against the indicators of healthy individuals. However, we have not established reliable differences between the quantitative content of pDCs in patients with hepatitis B and HIV-infected patients (p = 0.35 and p = 0.5 respectively), which may play a crucial role in the escape mechanisms of these infections from the action of the immune system. A particularly important role in the pathogenesis of these infections plays the functional state of pDCs. Shown stimulation of IFN production of pDCs in response to viral infection in patients with CHC and CHB vs index in healthy individuals. While patients with CHC production of IFN is significantly higher (203.7 ± 54.4) than in chronic hepatitis B (7.9 ± 1.9; p = 0.007), whereas in patients with HIV infection it is not detected and does not differ from that in healthy individuals. Conclusion. It is shown that the characteristics of the state of pDCs with infectious diseases of various etiologies have significant differences. The reduction of the content of pDCs compared with healthy individuals noted in chronic infections, however, the level of decrease depends on the etiology of the pathogen and stage of the disease. In such infectious diseases as viral hepatitis B and HIV infection there quantitative defect was marked in this cell population. Functional activity (interferonogenesis) in pDCs is maximally expressed when HCV is less significant with CHB, whereas in HIV-infected patients in General, paralyzed and does not differ from that of healthy people. These data demonstrate the close relationship activities of plasmacytoid dendritic cells with the pathogenesis and course of the studied infections, it is important to find new approaches to their treatment