Biomedical subjects

Shuyu Zhang

Publications and source records attributed to Shuyu Zhang.

At least 19 recordsLinked to original sources

PubMed2006

Meta-analysis of aggression or hostility events in randomized, controlled clinical trials of atomoxetine for ADHD.

BACKGROUND: We systematically examined potential aggression/hostility-related events in a meta-analysis of acute clinical trials of atomoxetine for attention-deficit/hyperactivity disorder (ADHD). METHODS: Pediatric patients from 14 trials of atomoxetine were subdivided into a placebo-controlled (atomoxetine n = 1308, placebo n = 806) or active comparator databases (atomoxetine n = 566, methylphenidate n = 472). A third database comprised adult patients from placebo-controlled studies (atomoxetine n = 541, placebo n = 405). A computerized search of adverse events and comments identified patients with potential aggression/hostility events. Mantel-Haenszel incidence differences (MHID) were calculated. RESULTS: In the placebo-controlled database, we observed 21 atomoxetine and 9 placebo patients with reported aggression/hostility events, MHID of .6% (95% confidence interval [CI]: -.4, 1.7). In the active comparator database, there were seven events in atomoxetine and four in methylphenidate patients, MHID = .2% (95% CI: -1.0,1.3). In the adult database, there were no events in 0 atomoxetine and one placebo patient, MHID = -.3% (95% CI: -.8, .2). CONCLUSIONS: Aggression/hostility-related events occurred in less than 2% of patients and were more frequent in pediatric patients treated with atomoxetine versus placebo (risk ratio of 1.33; not statistically significant). The risk of aggression/hostility events was similar in patients treated with atomoxetine or methylphenidate.

Adolescent↗

PubMed2006

A randomized, double-blind study of continuation treatment for attention-deficit/hyperactivity disorder after 1 year.

BACKGROUND: The efficacy of atomoxetine in maintaining symptom response following 1 year of treatment was assessed in children and adolescents (n = 163) with DSM-IV defined attention-deficit/hyperactivity disorder (ADHD). METHODS: Subjects had previously responded to atomoxetine acutely and had completed 1 year of double-blind atomoxetine treatment. They were then randomly assigned in double-blind fashion to continued atomoxetine or placebo substitution for 6 months. RESULTS: Atomoxetine was superior to placebo in preventing relapse (Wilcoxon test, p = .008) and in maintaining symptom response (ADHD Rating Scale IV score, p < .001). Among subjects assigned to discontinuation, the magnitude of symptom return was generally to a level of severity less than that observed at study entry. CONCLUSIONS: Following 1 year of treatment with atomoxetine, continued treatment over the ensuing 6 months was associated with superior outcomes compared with placebo substitution. However, there was considerable variability between individuals in the magnitude of symptom return after drug discontinuation, suggesting that some subjects treated with atomoxetine for a year with good results may consolidate gains made during drug treatment and could benefit from a medication-free trial to assess the need for ongoing drug treatment.

Adolescent↗

PubMed2006

General and efficient strategy for erythrinan and homoerythrinan alkaloids: syntheses of (+/-)-3-demethoxyerythratidinone and (+/-)-erysotramidine.

[reaction: see text] A general and efficient strategy to both aromatic-type and nonaromatic-type erythrinan and homoerythrinan alkaloids has been developed. This approach involves a key two-step sequence, an alkylation of a ketone with various N-substituted iodoacetamides followed by a N-acyliminium ion promoted intramolecular cyclization, and represents one of the shortest routes to erythrinan and homoerythrinan alkaloids. As the application, the formal total synthesis of (+/-)-3-demethoxyerythratidinone and the total synthesis of (+/-)-erysotramidine have been achieved, respectively.

Alkaloids↗

PubMed2006

A comparison of North American versus non-North American ADHD study populations.

Few large, prospective clinical studies in Europe have assessed the validity and applicability of research methods used to study ADHD in North America. To assess comparability of study populations, we examined baseline patient characteristics from a group of North American studies against those of a large European/African/Australian study. All studies used identical diagnostic assessments and inclusion criteria, with ADHD diagnosis and the presence of comorbid psychiatric conditions confirmed using the KSADS-PL. Raters were trained and assessed to ensure uniform diagnostic and symptom severity rating standards. Six hundred and four patients (mean age = 10.2 years) enrolled in the non-North American study, and 665 patients (mean age = 10.4 years) enrolled in the North American study. The proportion of girls was higher in the North American studies (29.2% vs. 10.4%, p < 0.001). In both groups, most patients had a positive family history of ADHD and previous stimulant treatment. Fewer had the inattentive subtype of ADHD, and mean severity was slightly higher in the non-North American study. Results demonstrate that, when a uniform set of rigorous, standardized diagnostic criteria are used by skilled clinicians, the patient populations identified are generally similar. This supports the practice of generalizing results from treatment studies across geographies.

Adrenergic Uptake Inhibitors↗

PubMed2006

Comorbid oppositional defiant disorder and the risk of relapse during 9 months of atomoxetine treatment for attention-deficit/hyperactivity disorder.

OBJECTIVE: To examine the influence of comorbid oppositional defiant disorder (ODD) on the relative risk (RR) of relapse during 9 months of treatment with atomoxetine for attention-deficit/hyperactivity disorder (ADHD). METHOD: Four hundred and sixteen children and adolescents with ADHD whose symptoms remitted during initial 10-week, open-label atomoxetine treatment were randomly assigned to continue with atomoxetine or placebo. RESULTS: In all, 43% met criteria for comorbid ODD. A total of 17% of patients with comorbid ODD relapsed (CGI-Severity score >or= 3 and ADHD Rating Scale total score of 90% or more of baseline at study entry on two consecutive visits) during atomoxetine treatment, compared with 26% of patients without comorbid ODD (RR 0.67, 95% CI 0.42-1.06). Mean time to relapse was not significantly different [mean (SE) days to relapse, ADHD/ +ODD: 215 (7.38); ADHD/-ODD: 211 (7.61); log rank p = 0.08]. This finding is placed within the context of atomoxetine affording an overall protection against relapse compared with placebo (RR 0.59, 95% CI 0.43-0.80). CONCLUSIONS: Comorbid ODD does not influence the rate of relapse of patients with ADHD during longer-term treatment with atomoxetine. Atomoxetine protects against the relapse of ADHD symptoms regardless of the presence or absence of comorbid ODD.

Adolescent↗

PubMed2005

Contributions of ATP, GTP, and redox state to nutritional stress activation of the Bacillus subtilis sigmaB transcription factor.

The general stress regulon of Bacillus subtilis is induced by activation of the sigma(B) transcription factor. sigma(B) activation occurs when one of two phosphatases responds to physical or nutritional stress to activate a positive sigma(B) regulator by dephosphorylation. The signal that triggers the nutritional stress phosphatase (RsbP) is unknown; however, RsbP activation occurs under culture conditions (glucose/phosphate starvation, azide or decoyinine treatment) that reduce the cell's levels of ATP and/or GTP. Variances in nucleotide levels in these instances may be coincidental rather than causal. RsbP carries a domain (PAS) that in some regulatory systems can respond directly to changes in electron transport, proton motive force, or redox potential, changes that typically precede shifts in high-energy nucleotide levels. The current work uses Bacillus subtilis with mutations in the oxidative phosphorylation and purine nucleotide biosynthetic pathways in conjunction with metabolic inhibitors to better define the inducing signal for RsbP activation. The data argue that a drop in ATP, rather than changes in GTP, proton motive force, or redox state, is the key to triggering sigma(B) activation.

Adenosine Triphosphate↗

PubMed2005

Coexpression patterns of sigma(B) regulators in Bacillus subtilis affect sigma(B) inducibility.

RsbT is an essential component of the pathway that activates the Bacillus subtilis sigma(B) transcription factor in response to physical stress. rsbT is located within an operon that includes the genes for its principal negative regulator (RsbS) and the stress pathway component that it activates (RsbU), as immediate upstream and downstream neighbors. In the current work we demonstrate that RsbT's ability to function is strongly influenced by coexpression with these adjoining genes. When rsbT is expressed at a site displaced from rsbS and rsbU, RsbT accumulates but it is unable to activate sigma(B) following stress. RsbT activity is restored if rsbT is cotranscribed at the alternative site with the genes that normally abut it. Additionally, an rsbS allele whose product allows constitutively high RsbT-dependent sigma(B) activity displays this activity in rsbS merodiploid strains only when cotranscribed with rsbT and is recessive to a wild-type rsbS allele only if the wild-type rsbS gene is not cotranscribed with an rsbT gene of its own. The data suggest that RsbS and RsbT are synthesized in equivalent amounts and interact coincidently with their synthesis to form stable regulatory complexes that maintain RsbT in a state from which it can be stress activated.

Bacillus subtilis↗

PubMed2004

Guanine nucleotides stabilize the binding of Bacillus subtilis Obg to ribosomes.

Obg is a GTP-binding protein of Bacillus subtilis with essential, but undefined roles in the bacterium's growth, sporulation, and stress responses. Obg orthologs are widely conserved among both bacteria and eukaryotes. Gel filtration and affinity blot assays have suggested that Obg may be ribosome-associated. In the current work, we continue an examination of the putative Obg:ribosome interaction. Velocity centrifugation analyses of crude B. subtilis extracts or purified Obg:ribosome mixtures suggest that Obg is initially ribosome-bound, but can separate from ribosomes during sedimentation in the absence of added nucleotides. Addition of either GTP, GDP or ATP to the gradient prolonged the Obg:ribosome association, while inclusion of a nonhydrolyzable GTP analog (5-guanylyl-imidodiphosphate) preserved it. The data strengthen the notion that Obg is a ribosome-associated protein, demonstrate that Obg's association with ribosomes is stabilized by GTP, and indicate that the ribosome-bound Obg can likely hydrolyze GTP and be released as a consequence.

Bacillus subtilis↗

PubMed2004

A prospective, multicenter, open-label assessment of atomoxetine in non-North American children and adolescents with ADHD.

OBJECTIVE: The aim of this study was to study treatment response to atomoxetine in a large, multicenter study of non-North American patients with ADHD. METHODS: A total of 604 children and adolescents with ADHD were enrolled in a 10-week open-label trial with atomoxetine prior to randomization to a double-blind relapse prevention phase at 33 sites in the United Kingdom, continental Europe, Israel, South Africa, and Australia. All patients had ADHD symptom severity at least 1.5 standard deviations above United States age and gender norms for their diagnostic subtype as measured by the investigator-scored ADHD Rating Scale (ADHD RS). Outcomes were assessed by analysis of change in the ADHD RS; functional and psychosocial outcomes were assessed using the Child Health Questionnaire (CHQ). RESULTS: At endpoint, ADHD RS total scores decreased by an average of 56.7%, and 69% of patients were rated as having no or minimal symptoms. Significant improvement was observed in psychosocial and functional outcomes. Discontinuations attributed to adverse events were < 4%. CONCLUSION: These open-label data, gathered in an international setting, add to our knowledge of the value of atomoxetine in treating ADHD symptoms, as well as its safety and tolerability.

Adolescent↗

PubMed2004

SeeDNA: a visualization tool for K-string content of long DNA sequences and their randomized counterparts.

An interactive tool to visualize the K-string composition of long DNA sequences including bacterial complete genomes is described. It is especially useful for exploring short palindromic structures in the sequences. The SeeDNA program runs on Red Hat Linux with GTK+ support. It displays two-dimensional (2D) or one-dimensional (1D) histograms of the K-string distribution of a given sequence and/or its randomized counterpart. It is also capable of showing the difference of K-string distributions between two sequences. The C source code using the GTK+ package is freely available.

Algorithms↗

PubMed2004

Relapse prevention in pediatric patients with ADHD treated with atomoxetine: a randomized, double-blind, placebo-controlled study.

OBJECTIVE: Attention-deficit/hyperactivity disorder (ADHD) is typically treated over extended periods; however, few placebo-controlled, long-term studies of efficacy have been reported. METHOD: In a global multicenter study, children and adolescents who responded to an initial 12-week, open-label period of treatment with atomoxetine, a nonstimulant treatment for ADHD, were randomized to continued atomoxetine treatment or placebo for 9 months under double-blind conditions. RESULTS: A total of 416 patients completed acute atomoxetine treatment and were randomized. At end point, atomoxetine was superior to placebo in preventing relapse defined as a return to 90% of baseline symptom severity (proportion relapsing: atomoxetine 65 of 292 [22.3%], placebo 47 of 124 [37.9%], p =.002). The proportion of patients with a 50% worsening in symptoms post-randomization was also lower on atomoxetine (atomoxetine 83 of 292 [28.4%], placebo 59 of 124 [47.6%], p <.001). Compared with patients in the placebo group, atomoxetine-treated patients had superior psychosocial functioning at end point. Discontinuations for adverse events were low in both groups, and tolerability was similar to that observed in acute treatment trials. CONCLUSIONS: In patients who responded favorably to 12 weeks of initial treatment, atomoxetine was superior to placebo in maintaining response for the ensuing 9 months. This result supports the value of maintenance treatment with atomoxetine in patients with ADHD who respond to initial treatment.

Atomoxetine Hydrochloride↗

PubMed2004

Associations between Bacillus subtilis sigmaB regulators in cell extracts.

The general stress regulon of Bacillus subtilis is induced by the activation of the sigma(B) transcription factor. Activation of sigma(B) occurs as a consequence of the dephosphorylation of its positive regulator RsbV by one of two phosphatases that respond to either physical or nutritional stress. The physical stress phosphatase (RsbU) requires a second protein (RsbT) for activity. Stress is thought to initiate a process that triggers the release of RsbT from a large inhibitory complex composed of multiple copies of two protein species, RsbR (and/or its paralogues) and RsbS. The stress-derived signal driving RsbT release is unknown, but it fails to develop in B. subtilis lacking either ribosome protein L11 or the ribosome-associated protein Obg. RsbR, RsbS, RsbT, Obg and ribosomes elute in common high-molecular-mass fractions during gel-filtration chromatography of crude B. subtilis extracts. This paper reports the investigation of the basis of this coelution by the examining of associations between these proteins in extracts prepared from wild-type and mutant B. subtilis, and Escherichia coli engineered to express RsbR, RsbS and RsbT. Large RsbR/RsbS complexes, distinct from ribosomes, were detected in extracts of both B. subtilis and E. coli. In E. coli, high-molecular-mass forms of RsbS were less abundant when RsbR was absent, but in B. subtilis, only when both RsbR and its principal paralogues were missing from the extract was this form less abundant. This finding is consistent with the notion that the RsbR paralogues, present in B. subtilis but not E. coli, can substitute for RsbR in such complexes. RsbT was not bound to RsbR/RsbS in any extract that was examined, including one prepared from a B. subtilis strain with an RsbS variant (RsbS59SA) that is believed to continuously associate with RsbT. The high-molecular-mass forms of RsbT were found to be Triton-sensitive and independent of any other B. subtilis protein for their formation. These probably represent RsbT aggregates. The data suggest that the contribution of ribosomes/Obg to sigma(B) activation does not involve formation of a stable association between these proteins and the Rsb complex. In addition, the binding of RsbT to RsbS/RsbR appears to be more labile than the binding between the previously analysed Rsb proteins which form inhibitory complexes. This, and the apparent proclivity of RsbT to aggregate, suggests an inherent instability in RsbT which may play a role in its regulation.

Bacillus subtilis↗

PubMed2004

Long-term treatment outcomes of depression with associated anxiety: efficacy of continuation treatment with fluoxetine.

BACKGROUND: Severity of anxiety does not appear to influence the antidepressant response to fluoxetine during acute treatment of major depressive disorder (MDD). We report a retrospective pooled analysis of 2 studies to assess the effect of associated anxiety on the efficacy of fluoxetine in the continuation treatment phase of MDD. METHOD: Patients whose MDD remitted (study 1) or responded (study 2) after approximately 12 to 13 weeks of open-label treatment with fluoxetine 20 mg daily were randomly assigned in double-blind fashion to placebo, continued treatment with fluoxetine 20 mg daily, or, in study 2 only, treatment with enteric-coated fluoxetine 90 mg once weekly, for at least 25 weeks. Both studies included male and female outpatients who met criteria for MDD as assessed by DSM-III-R (study 1) or DSM-IV (study 2). Patients were categorized into high anxiety (> or = 7) or low anxiety (< 7) subgroups based on baseline Hamilton Rating Scale for Depression (HAM-D) anxiety/somatization subfactor scores. Subgroups were compared by therapy for time from randomization to relapse and change in efficacy scores. RESULTS: No significant differences in time to relapse were observed between anxiety subgroups in either active treatment group. However, in patients switched to placebo for continuation treatment, the high anxiety subgroup had a significantly higher risk of relapse than those with low anxiety (risk ratio = 1.63, p =.013). Significant differences between anxiety groups were seen in change in HAM-D anxiety/somatization subfactor scores in the fluoxetine 20 mg and placebo treatment groups, and in change in HAM-D-17 scores in the placebo treatment group (p <.05). CONCLUSION: Although high baseline anxiety does not appear to impact the benefit of continuation therapy with fluoxetine, it does appear to predict increased risk of relapse in individuals who do not remain on antidepressant therapy for the duration of continuation treatment.

Adult↗

PubMed2004

[Identification of bryostatins in Bugula neritina extracts by high performance liquid chromatography and Q-Tof mass spectrometry].

A method with tandem high performance liquid chromatography (HPLC) and Q-Tof mass spectrometry (MS) has been established for the qualitative assay of bryostatins in Bugula neritina extracts. Ten bryostatins were well separated on a Polaris C18-5 column (4.6 mm i.d. x 200 mm, 5 microm) with methanol and water (80:20, v/v) as mobile phase. The bryostatins were qualitatively detected with the mass spectrometric detection. Ten bryostatins were found in the Bugula neritina collected from Gulf of Dayawan (Shenzhen, China). Mass spectra of the peaks led to the identification of nine known bryostatins that were bryostatins 4, 5, 6(9), 7, 8, 10, 16, 17, 18. Bryostatins 4, 5, 8, 10 could be further verified by the retention times of the corresponding standards. The two trace constituents, bryostatin 7 and 17, were for the first time found in Bugula neritina inhabiting in China sea. It is interesting that the result indicated the existence of a possibly new bryostatin in the mixture. The work above provides a quick and accurate assay method for the qualitative identification of the bryostatins in Bugula neritina extracts.

Animals↗

PubMed2003

Molecular handcuffing of the relaxosome at the origin of conjugative transfer of the plasmid R1162.

The assembly of plasmid-encoded proteins at a unique site (oriT) on the plasmid R1162, to form a complex called the relaxosome, is required for conjugative transfer of the plasmid and for negative regulation of neighboring promoters. Two-dimensional chloroquine gel electrophoresis was used to show that oriTs are physically coupled at the relaxosome. This interaction requires all the relaxosome proteins, which are assembled into a structure resulting in a decrease in the average linking number of the plasmid DNA in the cell. Molecules with higher superhelical densities are preferentially selected for assembly of the relaxosome. Genetic data obtained earlier indicate that the molecular coupling reported here is a 'handcuffing' reaction that contributes to the regulation of adjacent plasmid promoters. However, although these promoters affect the expression of the genes for replication, plasmid copy-control is regulated independently. This is the first time 'handcuffing' has been observed at an oriT, and its possible significance for transfer is discussed.

Bacterial Proteins↗

PubMed2003

RelA is a component of the nutritional stress activation pathway of the Bacillus subtilis transcription factor sigma B.

The general stress regulon of Bacillus subtilis is induced by the activation of the sigma(B) transcription factor. Activation of sigma(B) occurs when one of two phosphatases (RsbU and RsbP), each responding to a unique type of stress, actuates a positive regulator of sigma(B) by dephosphorylation. Nutritional stress triggers the RsbP phosphatase. The mechanism by which RsbP becomes active is unknown; however, its activation coincides with culture conditions that are likely to reduce the cell's levels of high-energy nucleotides. We now present evidence that RelA, a (p)ppGpp synthetase and the key enzyme of the stringent response, plays a role in nutritional stress activation of sigma(B). An insertion mutation that disrupts relA blocks the activation of sigma(B) in response to PO(4) or glucose limitation and inhibits the drop in ATP/GTP levels that normally accompanies sigma(B) induction under these conditions. In contrast, the activation of sigma(B) by physical stress (e.g., ethanol treatment) is not affected by the loss of RelA. RelA's role in sigma(B) activation appears to be distinct from its participation in the stringent response. Amino acid analogs which induce the stringent response and RelA-dependent (p)ppGpp synthesis do not trigger sigma(B) activity. In addition, neither a missense mutation in relA (relA240GE) nor a null mutation in rplK (rplK54), either of which is sufficient to inhibit the stringent response and RelA-dependent (p)ppGpp synthesis, fails to block sigma(B) activation by PO(4) or glucose limitation.

Bacillus subtilis↗

PubMed2003

[Screenings of 23 plant species in Beijing for volatile organic compound emissions].

The VOCs emissions from plants are mainly isoprene and monoterpenes, which account for 2/3 of the total emissions from biosphere. 23 kinds of typical plants in Beijing area were screened to estimate the emission rates of isoprene and monoterpenes by adopting a bag-enclosure sampling method followed by a GC-FID analysis. It was found that such deciduous trees as Sophora japnica and Salix babyloniaca etc. were mainly emitting isoprene and coniferous trees as Pinus tabulaetormis mainly released monoterpenes. The study also showed that the emission of isoprene were affected by both temperature and Photosynthetic Active Radiation (PAR), while monoterpene emissions were mainly temperature-dependent.

Butadienes↗

PubMedDate not supplied

Treatment approaches to major depressive disorder relapse. Part 1: dose increase.

OBJECTIVE: Although continuing antidepressant treatment after patients have responded to medication has been shown to greatly reduce the risk of relapse, this risk is not eliminated. A number of theories have been proposed to account for this apparent loss of efficacy. A common initial approach to managing relapse is to increase the dose of antidepressant. We prospectively evaluated the likelihood of response to increasing the fluoxetine doses in patients relapsing during a long-term efficacy study of two fluoxetine dosing regimens. METHOD: Patients meeting the DSM-IV criteria for major depressive disorder with modified HAMD17 scores > or =18 and CGI-severity scores > or =4 were treated for 13 weeks with open-label 20 mg/day fluoxetine in a multicenter US study. Responders (n = 501) were randomized to 20 mg fluoxetine daily, placebo, or 90 mg enteric-coated fluoxetine weekly for 25 weeks of double-blind continuation treatment. If the patients relapsed during the continuation phase, they were offered a 25-week optional rescue treatment phase during which the study medication dose was increased as follows: (1) patients on placebo had treatment with fluoxetine 20 mg/day reinitiated, (2) patients on fluoxetine 20 mg/day had their dose increased to 40 mg/day, and (3) patients on a 90-mg weekly dose had their dose increased to 90 mg twice a week. The results of the rescue phase for the latter two groups who relapsed while on continuation treatment with fluoxetine are reported. Response was defined as a 50% reduction in the modified HAMD17 score since time of relapse and a CGI-severity score < or =2. Additional efficacy analyses included HAMD and CGI-severity changes from baseline to endpoint. Safety measures included assessment of treatment-emergent adverse events, vital signs, and laboratory measures. RESULTS: Overall, patients relapsing during the continuation treatment responded to an increased dose (57% of the 40-mg-daily group and 72% of the enteric-coated 90-mg-twice-weekly group). Mean modified HAMD17 scores decreased from a mean of approximately 20 to below 8 and were maintained for up to 6 months in the responders. Thirty-five percent of patients either did not respond or initially responded but again relapsed after augmentation of medication. CONCLUSIONS: The patients relapsing after initially responding to fluoxetine can benefit from an increase in fluoxetine dose. These results also generally support increasing dose as a first-line treatment strategy for a patient who has relapsed while taking a previously effective dose of an antidepressant. Increasing enteric-coated fluoxetine 90 mg once weekly to twice weekly appeared to be as well-tolerated and effective in restoring response as increasing a daily fluoxetine dose from 20 to 40 mg.

Adult↗