Tracing Photoinduced Hydrogen Migration in Alcohol Dications from Time-Resolved Molecular-Frame Photoelectron Angular Distributions.

The recent implementation of attosecond and few-femtosecond X-ray pump/X-ray probe schemes in large-scale free-electron laser facilities has opened the way to visualize fast nuclear dynamics in molecules with unprecedented temporal and spatial resolution. Here, we present the results of theoretical calculations showing how polarization-averaged molecular-frame photoelectron angular distributions (PA-MFPADs) can be used to visualize the dynamics of hydrogen migration in methanol, ethanol, propanol, and isopropyl alcohol dications generated by X-ray irradiation of the corresponding neutral species. We show that changes in the PA-MFPADs with the pump-probe delay as a result of intramolecular photoelectron diffraction carry information on the dynamics of hydrogen migration in real space. Although visualization of this dynamics is more straightforward in the smaller systems, methanol and ethanol, one can still recognize the signature of that motion in propanol and isopropyl alcohol and assign a tentative path to it. A possible pathway for a corresponding experiment requires an angularly resolved detection of photoelectrons in coincidence with molecular fragment ions used to define a molecular frame of reference. Such studies have become, in principle, possible since the first XFELs with sufficiently high repetition rates have emerged. To further support our findings, we provide experimental evidence of H migration in ethanol-OD from ion-ion coincidence measurements performed with synchrotron radiation.

Femtosecond charge and molecular dynamics of I-containing organic molecules induced by intense X-ray free-electron laser pulses.

We studied the electronic and nuclear dynamics of I-containing organic molecules induced by intense hard X-ray pulses at the XFEL facility SACLA in Japan. The interaction with the intense XFEL pulse causes absorption of multiple X-ray photons by the iodine atom, which results in the creation of many electronic vacancies (positive charges) via the sequential electronic relaxation in the iodine, followed by intramolecular charge redistribution. In a previous study we investigated the subsequent fragmentation by Coulomb explosion of the simplest I-substituted hydrocarbon, iodomethane (CH3I). We carried out three-dimensional momentum correlation measurements of the atomic ions created via Coulomb explosion of the molecule and found that a classical Coulomb explosion model including charge evolution (CCE-CE model), which accounts for the concerted dynamics of nuclear motion and charge creation/charge redistribution, reproduces well the observed momentum correlation maps of fragment ions emitted after XFEL irradiation. Then we extended the study to 5-iodouracil (C4H3IN2O2, 5-IU), which is a more complex molecule of biological relevance, and confirmed that, in both CH3I and 5-IU, the charge build-up takes about 10 fs, while the charge is redistributed among atoms within only a few fs. We also adopted a self-consistent charge density-functional based tight-binding (SCC-DFTB) method to treat the fragmentations of highly charged 5-IU ions created by XFEL pulses. Our SCC-DFTB modeling reproduces well the experimental and CCE-CE results. We have also investigated the influence of the nuclear dynamics on the charge redistribution (charge transfer) using nonadiabatic quantum-mechanical molecular dynamics (NAQMD) simulation. The time scale of the charge transfer from the iodine atomic site to the uracil ring induced by nuclear motion turned out to be only ∼5 fs, indicating that, besides the molecular Auger decay in which molecular orbitals delocalized over the iodine site and the uracil ring are involved, the nuclear dynamics also play a role for ultrafast charge redistribution. The present study illustrates that the CCE-CE model as well as the SCC-DFTB method can be used for reconstructing the positions of atoms in motion, in combination with the momentum correlation measurement of the atomic ions created via XFEL-induced Coulomb explosion of molecules.

Functional roles of two polypeptide chains that compose an antigen-specific suppressor T cell factor.

The functional roles of the two polypeptide chains that compose the T cell suppressor factor (TsF) that mediates the antigen-specific and genetically restricted suppressor function were studied by using the heavy or light chains isolated from the conventional TsF or the 11S and 13S mRNA translation products of TsF. Either the heavy or the light chain of mRNA translation products reconstitutes the active TsF that suppresses the antibody response in an antigen-specific and genetically restricted manner when it is combined with the isolated heavy or light chain from the conventional TsF. As a consequence, the antigen-binding heavy chain mediates the antigen specificity of TsF. On the other hand, the I-J-positive light chain works as an element to determine the genetic restriction specificity. Thus, the identity of the histocompatibility between the I-J haplotypes on the light chain and the responding cell is essential for the functional expression of TsF. No genetic preference, however, was observed, in the association of the heavy and light chains of TsF.

Monoclonal antibodies that recognize the product controlled by a gene in the I-J subregion of the mouse H-2 complex.

The B cell hybridomas producing monoclonal antibodies (E10, D7, F4, H6, and D4) were established by the fusion of P3U1 or NS-1 murine myeloma cell lines and spleen cells of B10.A(5R) mice hyperimmunized with mitomycin C-treated B10.A(3R) spleen and thymus cells. Two types of monoclonal antibodies specific for the products controlled by a gene in the I-Jb subregion of the H-2 complex were characterized: one specific for the private type of I-Jb determinant, the other recognizing the cross-reactive determinant between the I-Jb and I-Jd products. By using these monoclonal reagents, the I-J-encoded product on the antigen-specific suppressor T cells was found to be expressed on their soluble suppressor factors. Furthermore, the I-Jb products were successfully detected not only on the T cell hybridoma with suppressor activity specific for keyhole limpet hemocyanin (KLH), but also on KLH-primed suppressor T cells enriched by antigen-coated petri dishes and concanavalin A-induced thymocyte blasts of C57BL/6 mice by complement-dependent cytotoxic assays and membrane fluorescence techniques.

Extrathymic development of V alpha 14-positive T cells.

It is known that rearrangement of the T cell antigen receptor (TCR) gene occurs in the thymus during T cell development and consequently results both in the deletion of DNA between the variable (V) and diversity/joining segments and in the formation of a circular DNA with recombination signal sequences. Here, we provide evidence that V alpha 14+ TCR gene rearrangements take place in extrathymic sites, such as bone marrow, liver, and intestine, but not in spleen, because we were able to detect frequent productive and nonproductive V alpha 14+ coding and signal sequences as a result of TCR rearrangements in extrathymic sites. Similar findings were also detected in athymic mice. Quantitative analysis shows that the relative amounts of V alpha 14 gene-mediated signal sequences in extrathymic tissues are higher than those in thymus. On the contrary, TCR rearrangements of V alpha 1.1 T cells, which are known to develop in the thymus, were mainly detected in the thymus, Peyer's patch, and spleen, but not in other extrathymic tissues, showing patterns distinct from V alpha 14 TCR rearrangements. These findings are evidence of extrathymic development of V alpha 14+ T cells. Differential characteristic TCR rearrangement patterns also indicate that distinct TCR repertoires are generated in different lymphoid tissues.

Cloning of the 62-kilodalton component of basic transcription factor BTF2.

Cloning of the mammalian basic transcription factors serves as a major step in understanding the mechanism of transcription initiation. The 62-kilodalton component (p62) of one of these transcription factors, BTF2 was cloned and overexpressed. A monoclonal antibody to this polypeptide inhibited transcription in vitro. Immunoaffinity experiments demonstrated that the 62-kilodalton component is closely associated with the other polypeptides present in the BTF2 factor. Sequence similarity suggests that BTF2 may be the human counterpart of RNA polymerase II initiation factor b from yeast.

Requirement for Valpha14 NKT cells in IL-12-mediated rejection of tumors.

A lymphocyte subpopulation, the Valpha14 natural killer T (NKT) cells, expresses both NK1.1 and a single invariant T cell receptor encoded by the Valpha14 and Jalpha281 gene segments. Mice with a deletion of the Jalpha281 gene segment were found to exclusively lack this subpopulation. The Valpha14 NKT cell-deficient mice could no longer mediate the interleukin-12 (IL-12)-induced rejection of tumors. Although the antitumor effect of IL-12 was thought to be mediated through natural killer cells and T cells, Valpha14 NKT cells were found to be an essential target of IL-12, and they mediated their cytotoxicity by an NK-like effector mechanism after activation with IL-12.

[A prosthetic ring annuloplasty with edge-to-edge repair for a treatment of severe tricuspid regurgitation].

A 59-year-old woman admitted to our hospital with shortness of breath and edema of the lower extremities was diagnosed with right ventricular failure stemming from severe tricuspid valve regurgitation (TR). She had undergone mitral valve replacement (MVR) with a mechanical valve at the age of 42. The approach to the heart was established via a right thoracotomy at the 4th intercostals space. A beating heart cardiopulmonary bypass procedure was performed in which tricuspid valve repair was performed with the edge-to-edge repair and MC3 annuloplasty system. The operative course was uneventful. This technique may be feasible and clinically effective in the treatment of severe TR.

Destabilization of neutrophil NADPH oxidase by ATP and other trinucleotides and its prevention by Mg(2+).

Neutrophil NADPH oxidase (O(2)(-) generating enzyme) activated in a cell-free system was deactivated by dilution. When ATP was included in dilution the deactivation was further accelerated. The deactivation by dilution was biphasic, and the half-life of the enzyme was significantly shortened by ATP in each phase. ADP and AMP had little effect on the enzyme longevity while GTP and CTP had a similar effect to ATP. Staurosporine, a wide-range inhibitor of protein kinases, had no effect on ATP-induced deactivation, suggesting that the effect was not due to a protein phosphorylation. Mg(2+) addition largely prevented the deactivation by ATP. Chemical crosslinking of the activated oxidase prevented the deactivation by dilution and ATP, suggesting that the deactivation is caused by dissociation of the oxidase complex. Estimation of actin filament (F-actin) showed that the F-actin level was markedly reduced by addition of ATP. The ATP effect on the deactivation was not prominent in a semi-recombinant system which does not contain cytosol. These results suggest that ATP-induced deactivation is largely due to the chelation of Mg(2+) and are consistent with the concept that Mg(2+) stabilizes the oxidase complex by stabilizing F-actin.

Cloning and characterization of two transcripts generated from the mel-13 gene positioned adjacent to the mammalian Polycomb group-related gene mel-18.

We previously isolated the mel-18 gene, a mammalian Polycomb group (PcG)-related gene with homology to bmi-1 oncogene. We show in this paper the existence of a new gene, mel-13, which overlapped with the mel-18 anti-oncogene. We discuss the relationships between mel-13 and the mel-18, bup, and Su(z)2 genes.

Preferential impairment of nitric oxide-mediated endothelium-dependent relaxation in human cervical arteries after irradiation.

BACKGROUND: Vascular abnormalities are a major cause of postoperative complications in irradiated tissues. Endothelial cell dysfunction characterized by diminished endothelium-dependent relaxation may be involved. We examined the endothelium-dependent relaxation and morphology of the endothelium in irradiated human cervical arteries. METHODS AND RESULTS: Irradiated arteries were taken from the neck region of patients who had radiation therapy. Arteries from patients who did not receive radiation therapy were used as controls. Endothelium-dependent relaxation to acetylcholine and A23187 was impaired in irradiated arteries. Norepinephrine-induced contraction and sodium nitroprusside-induced relaxation were unchanged. In control arteries, N(omega)-nitro-L-arginine and indomethacin each caused a partial inhibition of endothelium-dependent relaxation. In irradiated arteries, the impaired endothelium-dependent relaxation was unaffected by these agents, but it was abolished by high K(+). Acetylcholine produced similar degrees of hyperpolarization in control and irradiated arteries. Immunohistochemical examination for endothelial nitric oxide synthase indicated no expression in the endothelium of irradiated arteries. Electron scanning microscopy showed morphologically intact endothelial cells in irradiated arteries. CONCLUSIONS: In irradiated human cervical arteries, the nitric oxide- and prostacyclin-mediated endothelium-dependent relaxation, but not endothelium-derived hyperpolarizing factor-mediated relaxation, are specifically impaired, without significant morphological damage of the endothelium. The impaired nitric oxide-mediated relaxation was associated with a lack of endothelial nitric oxide synthase expression. Our results suggest the importance of impaired endothelial function in irradiated human blood vessels, which may partly explain the development of vascular stenosis and poor surgical wound healing in irradiated tissues.

Control of Mitosis by Phytochrome and a Blue-Light Receptor in Fern Spores.

The first mitosis in spores of the fern A. capillus-veneris was observed under a microscope equipped with Nomarski optics with irradiation from a safelight at 900 nm, and under a fluorescent microscope after staining with 4[prime],6-diamidino-2-phenylindole. During imbibition the nucleus remained near one corner of each tetrahedron-shaped dormant spore, and asymmetric cell division occurred upon brief irradiation with red light. This red light-induced mitosis was photoreversibly prevented by subsequent brief exposure to far-red light and was photo-irreversibly prevented by brief irradiation with blue light. However, neither far-red nor blue light affected the germination rate when spores were irradiated after the first mitosis. Therefore, the first mitosis in the spores appears to be the crucial step for photoinduction of spore germination. Furthermore, experiments using a microbeam of red or blue light demonstrated that blue light was effective only when exposed to the nucleus, and no specific intracellular photoreceptive site for red light was found in the spores. Therefore, phytochrome in the far-red absorbing form induces the first mitosis in germinating spores but prevents the subsequent mitosis in protonemata, whereas a blue-light receptor prevents the former but induces the latter.

Correlation between the expression of apoptosis-related bcl-2 and p53 oncoproteins and the carcinogenesis and progression of breast carcinomas.

The proto-oncogene bcl-2, which is implicated in the regulation of cell death by inhibiting apoptosis, is reported to be expressed in breast tissues. The wild-type p53 has been shown to induce apoptosis, which can be inhibited by bcl-2 expression. However, the role of bcl-2 and p53 expression in breast carcinogenesis has not been clarified. The purpose of this study was to evaluate bcl-2 and p53 expression in normal breast epithelia cells, as well as in intraductal and invasive cancerous lesions of breast cancer tissue using an immunohistochemical method and to clarify their role in the development of breast cancer. The nuclear accumulation of p53 was also evaluated by quantitative image analysis. Expression of bcl-2 was found in 79 of 82 (96%) normal ductal epithelial cells, in 50 of 63 (79%) intraductal carcinomas, and in 62 of 137 (45%) invasive carcinomas, respectively. Higher bcl-2 expression was observed in normal epithelial cells than in intraductal and invasive cancerous cells (P < 0.0001). Furthermore, bcl-2 positivity in intraductal lesions was significantly higher than in invasive cancerous lesions (P < 0.05). No p53 nuclear accumulation was observed in normal breast epithelial cells. Fifteen of 63 (23.8%) intraductal cancerous lesions and 41 of 137 (30%) invasive cancerous lesions were positive for p53 expression. An inverse relationship was shown between bcl-2 and p53 expression in invasive carcinomas. We demonstrated that bcl-2 expression exists in most of normal ductal epithelial cells and gradually decreases during the development of breast cancer, i.e. , from a normal epithelium to intraductal carcinoma, and from intraductal to invasive carcinoma, and that p53 expression may occur early in breast cancer development and increases during progression.

Tamoxifen-induced apoptosis in breast cancer cells relates to down-regulation of bcl-2, but not bax and bcl-X(L), without alteration of p53 protein levels.

Tamoxifen (TAM) has been shown to induce apoptosis in breast cancer cells. bcl-2 family genes, which can interact with each other, have been shown to interfere with apoptosis after various stimuli. In this study, we investigated the effects of TAM on bcl-2 family gene products bcl-2, bax, and bcl-X(L) and on p53 levels in estrogen receptor-positive MCF-7 breast cancer cells. We found that TAM induced time- and concentration-dependent down-regulation of bcl-2 at both the mRNA and protein level. Down-regulation of bcl-2 correlated with TAM-induced apoptosis. In addition, estradiol treatment significantly increased bcl-2 protein expression and blocked the reduction of bcl-2 by TAM. TAM did not, however, affect bax, bcl-X(L), or p53 expression at the mRNA or protein level. Our results demonstrate that TAM can induce apoptosis in a time- and dose-dependent manner by modulating bcl-2 levels in breast cancer cells, and down-regulation of bcl-2 induced by TAM was not accompanied by alterations in p53 levels.

The prevalence of abnormal cervical cytology in a sexually transmitted diseases clinic.

Women seeking sexually transmitted disease (STD) services are at high risk of human papillomavirus infections. Cervical cytological screening with Papanicolau staining (Pap smear) is not consistently offered at public STD clinics. We reviewed Pap smear results on a series of 1000 female STD clinic attendees, abstracted demographics, risk behaviours and STD diagnosis from the clinical record and tested for associations with abnormal Pap smear. In all, 5.7% of the satisfactory specimens (56/993) were abnormal; increasing age category, genital warts, and chlamydia infections were independently associated with an abnormal Pap smear in multivariate analysis. Routine Pap smear screening provided satisfactory results in the STD clinic and, where population-based programmes are not available, should be fully integrated into public STD care, (particularly in settings serving younger women).

Mammalian Polycomb group genes are categorized as a new type of early response gene induced by B-cell receptor cross-linking.

Polycomb group (PcG) genes were initially described in Drosophila melanogaster as regulators of the homeobox gene. Four mammalian homologues, mel-18, bmi-1, M33 and rae-28, are analyzed in this study. They not only regulate mammalian homeotic genes by analogy with their Drosophila counterparts, but also have some influence on the growth and differentiation of B lymphocytes. Here we report that these four mammalian PcG genes are rapidly induced after antigen-receptor cross-linking in B cells. Thus we would like to propose that mammalian PcG genes can be categorized as a new type of immediate early gene.

[Left ventricular reconstruction on the beating heart with retrograde coronary perfusion for repair of a left ventricular aneurysm associated with aortic regurgitation: report of a case].

A 67-year-old male was undergoing hemodialysis for renal failure. He had carotid stenosis, multiple liver cysts with impaired liver function, and mild aortic regurgitation in addition to a left ventricular aneurysm with reduced left ventricular function. We used intraaortic balloon pumping with a view to maintaining cerebral and hepatic blood flow during extracorporeal circulation. However, this procedure risked increased regurgitation at the aortic valve. Therefore, after aortic cross-clamping, we performed the left ventricular reconstruction while cardiac pulsation was maintained by retrograde coronary perfusion using normothermic oxygenated blood. Coronary artery bypass grafting followed after the cross-clamp was released. The patient's postoperative progress was smooth and he was discharged on 14th postoperative day.

Beta 1 adrenoceptor mediated decrease in pHi in quiescent ventricular myocardium.

OBJECTIVE: The aims were to examine the effect of beta adrenergic stimulation on the intracellular pH (pHi) and to compare it with that of alpha adrenergic stimulation in ventricular myocardium. METHODS: Using conventional and ion selective electrodes membrane potential and pHi were measured simultaneously in quiescent papillary muscles of guinea pigs in HEPES or bicarbonate buffered solution. Isoprenaline and propranolol (1 microM) plus phenylephrine (30 microM) were used to stimulate beta and alpha adrenoceptors, respectively. In order to evaluate underlying mechanism(s) of beta adrenoceptor mediated pHi change, effects of Na(+)-H+ exchange, Cl(-)-HCO3- exchange, Na(+)-HCO3- symport, and glycolysis blockers on the pHi change were examined. RESULTS: Isoprenaline (1 microM) produced a decrease in pHi of 0.08(SEM 0.01) pH units and a transient depolarisation of the resting membrane. The isoprenaline induced intracellular acidosis was blocked by the beta 1 blocker atenolol (10 microM) but not by the beta 2 blocker ICI 118,551 (0.1 microM). Forskolin also produced a decrease in pHi of 0.06(0.03) pH units. In contrast, alpha adrenergic stimulation produced an increase in pHi, which was abolished by 1 mM amiloride, an Na(+)-H+ exchange blocker. In the presence of amiloride, the isoprenaline induced decrease in pHi was rather enhanced. 4,4'-Diisothiocyanostilbene-2,2'-disulphonic acid (DIDS, 1 mM), a blocker of Cl(-)-HCO3- exchange and the Na(+)-HCO3- symport system, failed to affect the isoprenaline induced pHi decrease in bicarbonate buffered solution. However, pretreatment with 2-deoxyglucose or iodoacetic acid abolished the isoprenaline induced pHi decrease. CONCLUSIONS: beta 1 Adrenoceptor stimulation causes intracellular acidosis via the enhanced glycolysis, and the Na(+)-H+ exchange system appears to play a compensatory role. The beta 1 adrenoceptor mediated intracellular acidosis may modulate inotropic response to adrenergic stimulation in ventricular myocardium.

Delayed afterdepolarisations and triggered activity in canine Purkinje fibres treated with neuraminidase.

We investigated the electrophysiological alterations induced by the removal of sialic acid from the sarcolemma in canine Purkinje fibres. About 70% of total sialic acid content of Purkinje fibres was removed by 120 min of exposure to neuraminidase (1 U X ml-1). The treatment with neuraminidase did not change any of the action potential characteristics at normal Ca2+ concentration (2.7 mmol X litre-1). However, action potential duration and maximum upstroke velocity of phase zero of the action potential were reduced to a greater degree in neuraminidase-treated Purkinje fibres than in non-treated controls at high Ca2+ concentration (8.1 mmol X litre-1). At high Ca2+ concentration, delayed afterdepolarisations were induced in five out of nine neuraminidase-treated Purkinje fibres and triggered activity was observed in two, when driven in trains of 20 stimuli of different cycle length (1000 to 180 ms). No discernible delayed afterdepolarisations were observed in nine non-treated control Purkinje fibres. In addition, the amplitude of delayed afterdepolarisations induced by ouabain (0.2 mumol X litre-1) in neuraminidase-treated Purkinje fibres was larger than non-treated controls. These findings suggest that sialic acid residues of glycocalyx function as a kind of barrier to Ca2+ influx.