Окситоцин та його роль у контролі внутрішньоклітинного рівня іонів кальцію в міометрії

В огляді висвітлено сучасні дані щодо молекулярних та мембранних механізмів дії утеротонічного пептидного гормону окситоцину на гомеостаз Са^2+ у міоцитах матки та активність систем пасивного та активного транспортування цього катіону, локалізованих в субклітинних структурах міометрія. Встановлені біохімічні механізми активації окситоцином та тапсигаргіном транспортування Сa^2+ до цитоплазми клітин міометрія. Такий процес надходження іонів кальцію з позаклітинного простору одержав назву capacitative cation entry (CCE), або такий, який активується спустошенням внутрішньоклітинних кальцієвих пулів. Показано, що клітини міометрія невагітних жінок та клітинна лінія PHM1-41 з міометрія вагітних жінок експресують mRNA hTrpС1, 3, 4, 6, 7. Синтетичний аналог діацилгліцеролу OAG спричинює виникнення осциляцій концентрації Са^2+ у клітинах міометрія. Інгібітори протеїнкінази С не впливають на здатність OAG спричинювати осциляції концентрації Са^2+. Зроблено висновок, що дія синтетичного аналога діацилгліцеролу OAG у клітинах міометрія не опосередковується активацією протеїнкінази С. Результати експериментів, що були виконані на фракції везикул плазматичних мембран міометрія, показали, що окситоцин не впливає на базальну кальцієву проникність цієї мембрани. Встановлено, що пептидний гормон частково інгібує накопичення Са^2+ у фракції плазматичних мембран міометрія. Окситоцин також частково гальмує активність кальцієвої помпи саркоплазматичного ретикулума матки. Запропонована концептуальна схема регуляції окситоцином обміну Са^2+ в міометрії.Работа посвящена обсуждению молекулярных и мембранных механизмов действия утеротонического пептидного гормона окситоцина на гомеостаз Са^2+ в миоцитах матки и активность систем пассивного и активного транспорта этого катиона, локализованных в субклеточных структурах миометрия. Установлены биохимические механизмы активации окситоцином и тапсигаргином дополнительного входа Са^2+ в цитоплазму клеток миометрия. Такой транспорт Са^2+ из внеклеточной среды получил название capacitative cation entry (CCE), или такой, который активируется опустошением внутриклеточных кальциевых пулов. Было показано, что в клетках миометрия небеременных женщин, а также клетках культуры РНМ1-41 из миометрия беременных женщин присутствуют mRNA hTrpС1,3,4,6,7. Синтетический аналог диацилглицерола (OAG) вызывает осцилляции концентрации Са^2+ в клетках миометрия. Ингибиторы протеинкиназы С не влияли на способность OAG вызывать осцилляции концентрации Са^2+. Сделан вывод о том, что действие синтетического аналога диацилглицерола в клетках миометрия не опосредуется активацией протеинкиназы С. На основании результатов экспериментов, проведенных на фракции везикул плазматических мембран миометрия, сделан вывод о том, что окситоцин не влияет на пассивный выход Са^2+ из везикул. Показано, что пептидный гормон частично ингибирует накопление Са^2+ во фракции везикул плазматических мембран миометрия. Окситоцин также частично ингибирует активность кальциевой помпы саркоплазматического ретикулума клеток миометрия. Предложена концептуальная схема регуляции окситоцином обмена Са^2+ в миометрии.The work deals with the study of molecular and membrane mechanisms of uterotonic peptide hormone oxytocin action on Ca ions homeostasis in the uterus myocites and activity of passive and active transport systems of this cation, localized in the myometrium subcellular structures. Biochemical mechanisms of additional Ca^2+ influx into the myometrium cells from extracellular environment activated by oxytocin and thapsigargin were determined. Such Ca^2+ influx has got the name of capacitative cation entry (CCE), or which is activated by intracellular store depletion (store-operated calcium entry). It was shown that cells from the nonpregnant human myometrium and PHM1-41 cells (immortalized pregnant human myometrial cells) expressed endogenous hTrpC1, 3, 4, 6 and 7 mRNA. The membrane-permeable derivative of diacylglycerol (OAG) stimulated an increase in oscillations of intracellular free Ca^2+ concentration in PHM1-41 and myometrium cells. OAG-induced Ca^2+-oscillations were not affected by inhibition of PKC. It was proved that hTrpC channels take part in the regulation of free Ca ions concentration in the myometrium cells. On the basis of results of experiments, conducted on myometrium plasma membrane fraction, the conclusion was made that oxytocin does not influence the passive Ca^2+ efflux. It was shown that peptyde hormone partially inhibited Ca^2+ accumulation in plasma membrane fraction. Oxytocin also partially inhibited endoplasmic reticulum calcium pump activity of the myometrium cells. The conceptual pattern of myometrial Ca^2+ exchange regulation by oxytocin is offered

High-spin structures in 155Tb and signature splitting systematics of the πh11/2 bands in odd A≈160 nuclei

The reactions 152Sm(7Li,4n) at 45 MeV and 124Sn(36S,p4n) at 165 MeV were used to study high-spin states of the N590 nucleus 155Tb. Previously known bands have been greatly extended in spin (I'45\) and a new decoupled sequence was identified. Several band crossings or quasiparticle alignments have been observed in each of the structures, and as a result a configuration assignment has been given to the new band. B(M1)/B(E2) transition strength ratios have been extracted from the data and comparisons were made with theoretical predictions. A comprehensive analysis of the signature splitting in the energy levels and B(M1)/B(E2) ratios for the ph11/2 bands of the A'160 region has been performed. Possible interpretations for the observed trends in the signature splitting of these structures are discussed

Second proton and neutron alignments in the doubly-odd nuclei 154,156Tb

High-spin states in the doubly-odd nuclei 154,156Tb have been populated in two separate experiments using the 36S1124Sn reaction at different beam energies ~160 and 175 MeV!. The yrast structures of both nuclei were extended to much higher spin (I<48\) than previously known and several quasiparticle alignments have been identified. These include the second neutron alignment and a clear delineation of the second proton crossing in 156Tb. Systematics of these crossings for odd-Z nuclei and comparisons with results of cranked shell model calculations are discussed

Rotational band structures in N=89 153Gd

The reactions 152Sm(α,3n) at 37 MeV and 124Sn(36S,α3n) at 165 MeV were used to produce high-spin states in the transitional rare-earth nucleus 153Gd. Significant extensions in angular momentum and excitation energy with respect to earlier work were achieved and several new rotational sequences were observed. The rotational behavior of 153Gd is described in terms of quasiparticle assignments and the observed alignment properties are analyzed within the framework of the cranked shell model. Detailed comparisons with other N=89 nuclei are presented. These have led to corrections to the 157Er level scheme

Superdeformed band in 155Dy: Where does the "island" of superdeformation end?

A superdeformed band of 15 transitions has been found in the 155Dy nucleus. The measurement was performed with a backed target and the large deformation was inferred from the measured Doppler shifts. The new band displays an intensity pattern much different from typical superdeformed bands in this mass region. The dynamic moment of inertia is essentially identical to that of band 1 in 153Dy and is somewhat larger than those of the yrast superdeformed bands in 152, 154Dy, suggesting that the associated configuration has an additional N = 7, j15/2 intruder orbital occupied with respect to the 154Dy core

Search for composite and exotic fermions at LEP 2

A search for unstable heavy fermions with the DELPHI detector at LEP is reported. Sequential and non-canonical leptons, as well as excited leptons and quarks, are considered. The data analysed correspond to an integrated luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172 GeV and 161 GeV. The search for pair-produced new leptons establishes 95% confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2, depending on the channel. The search for singly produced excited leptons and quarks establishes upper limits on the ratio of the coupling of the excited fermio

Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

The $B^0$-$\bar B^0$ oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives $\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)}$ ps$^{-1}$.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

Search for lightest neutralino and stau pair production in light gravitino scenarios with stau NLSP

Promptly decaying lightest neutralinos and long-lived staus are searched for in the context of light gravitino scenarios. It is assumed that the stau is the next to lightest supersymmetric particle (NLSP) and that the lightest neutralino is the next to NLSP (NNLSP). Data collected with the Delphi detector at centre-of-mass energies from 161 to 183 \GeV are analysed. No evidence of the production of these particles is found. Hence, lower mass limits for both kinds of particles are set at 95% C.L.. The mass of gaugino-like neutralinos is found to be greater than 71.5 GeV/c^2. In the search for long-lived stau, masses less than 70.0 to 77.5 \GeVcc are excluded for gravitino masses from 10 to 150 \eVcc . Combining this search with the searches for stable heavy leptons and Minimal Supersymmetric Standard Model staus a lower limit of 68.5 \GeVcc may be set for the stau mas

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio