The Unimolecular Reaction Of (ch3)3cno Following N-π* Excitation With A Tunable Dye Laser

The predissociation of (CH3)3CNO following the 570-710 nm laser excitation of the n-π transition is reported. The small fluorescence quantum yield and its short lifetime (<20 ns) indicate efficient radiationless processes prior to dissociation. NO is the major dissociation product and its concentration was monitored in real time by using the two-photon laser excited fluorescence technique. The NO yield as a function of wavelength followed very closely the absorption contours of (CH3) 3CNO. The NO production rate was > 108 s-1 at all wavelengths studied and this rate is too fast to be consistent with a mechanism involving a radiationless transition to the ground electronic state followed by energy randomization and dissociation. Alternative predissociation mechanisms are considered. © 1983 American Institue of Physics.7863785379

Molecule-surface collision-induced dissociation of internally excited NO2 on MgO ( 100) *

- AbStl ¶lCt Collision-induced dissociation (CID) of highly excited NOs in the mixed 2A,/2B2 electronic system has been observed for well characterized MgO ( 100) surfaces with parent and product angular resolution at various internal energies. NO state distributions were probed by two-photon, two-frequency ionization, and its yield was found to track the NO2 absorption spectrum, confirming the CID mechanism. The angular dependence of the NO state distribution indicates that CID occurs following direct inelastic scattering rather than trapping-desorption

365 nm photon-induced dynamics of CINO adsorbed on MgO(100)

Temperature programmed desorption (TPD) and 365 nm photolysis of ClNO adsorbed on MgO(100) at 90 K were investigated under ultrahigh vacuum conditions. The crystal was treated in a way that largely eliminated oxygen vacancies and yielded a relatively smooth surface. Angularly resolved time-of-flight (TOF) mass spectra and state-selective resonance-enhanced multiphoton ionization (REMPI) spectra of NO photoproducts were obtained. The TPD data indicate that ClNO desorbs at surface temperatures above 160 K for exposures (0) below 0.2 Langmuirs (L), while for higher values of 0 the main desorption peak is near 120 K. The higher temperature feature, which saturates at 0~0.3 L, is probably associated with binding to defect sites. Thermal desorption is believed to be molecular at all coverages. Irradiation at 365 nm for 0.1~0~5.0 L yields products having low average translational energies and broad translational energy distributions. NO fragment REMPI spectra were recorded at 0;;'0.7 L. The rotational distributions could be fit with a temperature of 110::1: 10 K, i.e., comparable to that of the substrate. These results differ from those obtained in the photodissociation of gas-phase CINO, where the NO fragment has high translational and rotational energies. However, the present results are similar to those obtained on rougher Mg0(100) surfaces. Possible mechanisms are discussed

Adverse Events in a Cohort of HIV Infected Pregnant and Non-Pregnant Women Treated with Nevirapine versus Non-Nevirapine Antiretroviral Medication

BACKGROUND: Predictors of adverse events (AE) associated with nevirapine use are needed to better understand reports of severe rash or liver enzyme elevation (LEE) in HIV+ women. METHODOLOGY: AE rates following ART initiation were retrospectively assessed in a multi-site cohort of 612 women. Predictors of onset of rash or LEE were determined using univariate and multivariate analyses. PRINCIPAL FINDINGS: Of 612 subjects, 152 (24.8%) initiated NVP-based regimens with 86 (56.6%) pregnant; 460 (75.2%) initiated non-NVP regimens with 67 (14.6%) pregnant. LEE: No significant difference was found between regimens in the development of new grade ≥2 LEE (p  =  0.885). Multivariate logistic regression demonstrated an increased likelihood of LEE with HCV co-infection (OR 2.502, 95% CI: 1.04 to 6, p =  0.040); pregnancy, NVP-based regimen, and baseline CD4 >250 cells/mm(3) were not associated with this toxicity. RASH: NVP initiation was associated with rash after controlling for CD4 and pregnancy (OR 2.78; 95%CI: 1.14-6.76), as was baseline CD4 >250 cells/mm(3) when controlling for pregnancy and type of regimen (OR 2.68; 95% CI: 1.19-6.02 p  =  0.017). CONCLUSIONS: CD4 at initiation of therapy was a predictor of rash but not LEE with NVP use in HIV+ women. Pregnancy was not an independent risk factor for the development of AEs assessed. The findings from this study have significant implications for women of child-bearing age initiating NVP-based ART particularly in resource limited settings. This study sheds more confidence on the lack of LEE risk and the need to monitor rash with the use of this medication

Moult cycle specific differential gene expression profiling of the crab Portunus pelagicus

Background: Crustacean moulting is a complex process involving many regulatory pathways. A holistic approach to examine differential gene expression profiles of transcripts relevant to the moulting process, across all moult cycle stages, was used in this study. Custom cDNA microarrays were constructed for Portunus pelagicus. The printed arrays contained 5000 transcripts derived from both the whole organism, and from individual organs such as the brain, eyestalk, mandibular organ and Y-organ from all moult cycle stages.Results: A total of 556 clones were sequenced from the cDNA libraries used to construct the arrays. These cDNAs represented 175 singletons and 62 contigs, resulting in 237 unique putative genes. The gene sequences were classified into the following biological functions: cuticular proteins associated with arthropod exoskeletons, farnesoic acid O-methyltransferase (FaMeT), proteins belonging to the hemocyanin gene family, lectins, proteins relevant to lipid metabolism, mitochondrial proteins, muscle related proteins, phenoloxidase activators and ribosomal proteins. Moult cycle-related differential expression patterns were observed for many transcripts. Of particular interest were those relating to the formation and hardening of the exoskeleton, and genes associated with cell respiration and energy metabolism.Conclusions: The expression data presented here provide a chronological depiction of the molecular events associated with the biological changes that occur during the crustacean moult cycle. Tracing the temporal expression patterns of a large variety of transcripts involved in the moult cycle of P. pelagicus can provide a greater understanding of gene function, interaction, and regulation of both known and new genes with respect to the moulting process

The vertebrate muscle Z-disc: sarcomere anchor for structure and signalling

The Z-disc, appearing as a fine dense line forming sarcomere boundaries in striated muscles, when studied in detail reveals crosslinked filament arrays that transmit tension and house myriads of proteins with diverse functions. At the Z-disc the barbed ends of the antiparallel actin filaments from adjoining sarcomeres interdigitate and are crosslinked primarily by layers of α-actinin. The Z-disc is therefore the site of polarity reversal of the actin filaments, as needed to interact with the bipolar myosin filaments in successive sarcomeres. The layers of α-actinin determine the Z-disc width: fast fibres have narrow (~30–50 nm) Z-discs and slow and cardiac fibres have wide (~100 nm) Z-discs. Comprehensive reviews on the roles of the numerous proteins located at the Z-disc in signalling and disease have been published; the aim here is different, namely to review the advances in structural aspects of the Z-disc

Pharmacogenetic & Pharmacokinetic Biomarker for Efavirenz Based ARV and Rifampicin Based Anti-TB Drug Induced Liver Injury in TB-HIV Infected Patients

BACKGROUND: Implication of pharmacogenetic variations and efavirenz pharmacokinetics in concomitant efavirenz based antiviral therapy and anti-tubercular drug induced liver injury (DILI) has not been yet studied. We performed a prospective case-control association study to identify the incidence, pharmacogenetic, pharmacokinetic and biochemical predictors for anti-tubercular and antiretroviral drugs induced liver injury (DILI) in HIV and tuberculosis (TB) co-infected patients. METHODS AND FINDINGS: Newly diagnosed treatment naïve TB-HIV co-infected patients (n = 353) were enrolled to receive efavirenz based ART and rifampicin based anti-TB therapy, and assessed clinically and biochemically for DILI up to 56 weeks. Quantification of plasma efavirenz and 8-hydroxyefaviernz levels and genotyping for NAT2, CYP2B6, CYP3A5, ABCB1, UGT2B7 and SLCO1B1 genes were done. The incidence of DILI and identification of predictors was evaluated using survival analysis and the Cox Proportional Hazards Model. The incidence of DILI was 30.0%, or 14.5 per 1000 person-week, and that of severe was 18.4%, or 7.49 per 1000 person-week. A statistically significant association of DILI with being of the female sex (p = 0.001), higher plasma efavirenz level (p = 0.009), efavirenz/8-hydroxyefavirenz ratio (p = 0.036), baseline AST (p = 0.022), ALT (p = 0.014), lower hemoglobin (p = 0.008), and serum albumin (p = 0.007), NAT2 slow-acetylator genotype (p = 0.039) and ABCB1 3435TT genotype (p = 0.001). CONCLUSION: We report high incidence of anti-tubercular and antiretroviral DILI in Ethiopian patients. Between patient variability in systemic efavirenz exposure and pharmacogenetic variations in NAT2, CYP2B6 and ABCB1 genes determines susceptibility to DILI in TB-HIV co-infected patients. Close monitoring of plasma efavirenz level and liver enzymes during early therapy and/or genotyping practice in HIV clinics is recommended for early identification of patients at risk of DILI

Cause of Death and Predictors of All-Cause Mortality in Anticoagulated Patients With Nonvalvular Atrial Fibrillation : Data From ROCKET AF

M. Kaste on työryhmän ROCKET AF Steering Comm jäsen.Background-Atrial fibrillation is associated with higher mortality. Identification of causes of death and contemporary risk factors for all-cause mortality may guide interventions. Methods and Results-In the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF) study, patients with nonvalvular atrial fibrillation were randomized to rivaroxaban or dose-adjusted warfarin. Cox proportional hazards regression with backward elimination identified factors at randomization that were independently associated with all-cause mortality in the 14 171 participants in the intention-to-treat population. The median age was 73 years, and the mean CHADS(2) score was 3.5. Over 1.9 years of median follow-up, 1214 (8.6%) patients died. Kaplan-Meier mortality rates were 4.2% at 1 year and 8.9% at 2 years. The majority of classified deaths (1081) were cardiovascular (72%), whereas only 6% were nonhemorrhagic stroke or systemic embolism. No significant difference in all-cause mortality was observed between the rivaroxaban and warfarin arms (P=0.15). Heart failure (hazard ratio 1.51, 95% CI 1.33-1.70, P= 75 years (hazard ratio 1.69, 95% CI 1.51-1.90, P Conclusions-In a large population of patients anticoagulated for nonvalvular atrial fibrillation, approximate to 7 in 10 deaths were cardiovascular, whereasPeer reviewe