Surface relaxations, current enhancements, and absolute distances in high resolution scanning tunneling microscopy.

We have performed the most realistic simulation to date of the operation of a scanning tunneling microscope. Probe-sample distances from beyond tunneling to actual surface contact are covered. We simultaneously calculate forces, atomic displacements, and tunneling currents, allowing quantitative comparison with experimental values. A distance regime below which the probe becomes unstable is identified. It is shown that the real distance differs substantially from previous estimates because of large atomic displacements on the surface and at the probe tip.

Sertraline treatment of panic disorder: results of a long-term study.

OBJECTIVE: To investigate the long-term efficacy, prevention of relapse and safety of sertraline in the treatment of panic disorder. METHOD: This study consisted of 52 weeks of open-label sertraline treatment (n=398) followed by a 28 weeks of a double-blind, placebo-controlled discontinuation trial (n=183). RESULTS: Ninety-three patients were randomized to sertraline and 90 were randomized to placebo. Discontinuation due to insufficient clinical response occurred in 23.6% of placebo-treated patients and 12.0% of sertraline-treated patients (log-rank test, P=0.040). Thirty-three per cent of placebo-treated patients had an exacerbation of panic symptomatology, versus 13% of sertraline-treated patients (log-rank test, P=0.005). Abrupt cessation of sertraline resulted in dizziness (4.3% sertraline vs. 16.9% placebo; P=0.007) and insomnia (4.3% sertraline vs. 15.7% placebo; P=0.013) occurring at significantly higher rates. CONCLUSION: Long-term sertraline treatment was effective in preventing relapse of panic disorder, well tolerated and associated with minimal discontinuation symptoms.

Long-term sertraline treatment of children and adolescents with obsessive-compulsive disorder.

OBJECTIVE: To evaluate the safety and effectiveness of sertraline in the long-term treatment of pediatric obsessive-compulsive disorder (OCD). METHOD: Children (6-12 years; n= 72) and adolescents (13-18 years; n = 65) with DSM-III-R-defined OCD who had completed a 12-week, double-blind, placebo-controlled sertraline study were given open-label sertraline 50 to 200 mg/day in this 52-week extension study. Concomitant psychotherapy was allowed during the extension study Outcome was evaluated by the Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS), National Institute of Mental Health Global Obsessive-Compulsive Scale, and Clinical Global Impression Severity (CGI-S) and Improvement (CGI-I) scores. RESULTS: Significant improvement (p < .0001) was demonstrated on all four outcome parameters on an intent-to-treat analysis for the overall study population (n = 132), as well as the child and the adolescent samples. At endpoint, 72% of children and 61% of adolescents met response criteria (>25% decrease in CY-BOCS and a CGI-I score of 1 or 2). Significant (p < .05) improvements were also demonstrated from the extension study baseline to endpoint on all outcome parameters in those patients who received sertraline during the 12-week, double-blind acute study. Long-term sertraline treatment was well tolerated, and there were no discontinuations due to changes in vital signs, laboratory values, or electrocardiograms. CONCLUSION: Sertraline (50-200 mg/day) was effective and generally well tolerated in the treatment of childhood and adolescent OCD for up to 52 weeks. Improvement was seen with continued treatment.

Panic disorder and response to sertraline: the effect of previous treatment with benzodiazepines.

More than 50% of patients who seek psychiatric care for panic disorder have previously received prescriptions for a benzodiazepine (BZ). Research on the treatment of generalized anxiety suggests that a history of BZ exposure might decrease the efficacy and tolerability of treatment with a serotonergic anxiolytic. This study examines the effect of prior BZ treatment on the efficacy and tolerability of sertraline treatment for panic disorder. Data were pooled (N = 705) from four double-blind, placebo-controlled studies of the efficacy of sertraline for the treatment of panic. Two of the studies were 12-week fixed-dose studies with starting doses of 50 mg, whereas 2 were flexible-dose studies of 10-week duration with starting doses of 25 mg. The effect of study treatment on the frequency of panic attacks, Clinical Global Impressions (CGI) Improvement Scale, and tolerability was examined for patients with or without prior BZ treatment. The efficacy of sertraline was not affected by prior treatment with BZs. The mean endpoint reduction in panic attack frequency was identical in patients with or without prior BZ use: 79% vs. 80% (not significant). A history of good versus poor response to prior BZ treatment did not significantly influence CGI responder rates for sertraline-treated patients (67% vs. 61%, respectively). Sertraline CGI responder rates were significantly greater than placebo response, which was 47% for the good-response prior-BZ subgroup (p = 0.007), and 36% for the poor-response BZ subgroup (p = 0.013). Placebo response was lower in patients with any prior BZ use by 10% on an intent-to-treat last-observation-carried-forward analysis (p = 0.106) and by 15% on a completer analysis (p = 0.045). Prior BZ use did not influence either rates of adverse events or discontinuation rates within the first 3 weeks in patients treated with either sertraline or placebo. Sertraline is both well-tolerated and has significant efficacy in patients with panic disorder, including the subset of patients with panic disorder who have previously been treated with BZs.

Is placebo response the same as drug response in panic disorder?

OBJECTIVE: The authors used seven definitions of response in panic disorder to compare patient-rated improvements in quality of life between patients with panic disorder who responded to sertraline and those who responded to placebo. METHOD: They combined and examined data from two multicenter, randomized, double-blind, parallel-group, flexible-dose studies of panic disorder (N=302). RESULTS: Significant differences in quality of life between patients who responded to sertraline and those who responded to placebo were apparent across all the definitions of clinical response. CONCLUSIONS: Patients who respond to placebo in panic disorder treatment studies may show symptom relief but may not experience improvement in quality of life. Determinations of quality of life should be included as components of both standard clinical assessment and clinical treatment studies of patients with panic disorder.

Sertraline treatment of panic disorder: response in patients at risk for poor outcome.

BACKGROUND: More than one third of panic disorder patients have a chronic and/or recurrent form of the disorder, accounting for much of the individual and societal cost associated with the illness. Six clinical variables have been most consistently identified as high-risk predictors of poor outcome: (1) panic severity, (2) presence of agoraphobia, (3) comorbid depression, (4) comorbid personality disorder, (5) duration of illness, and (6) female sex. No published research has systematically examined the differential antipanic efficacy of selective serotonin reuptake inhibitors in patients at high risk for poor outcome. METHOD: Data were pooled (N = 664) from 4 double-blind, placebo-controlled studies of the efficacy of sertraline for the treatment of DSM-III-R panic disorder. Two of the studies were 12-week fixed-dose studies with starting daily doses of sertraline, 50 mg, and 2 were 10-week flexible-dose studies with starting daily doses of sertraline, 25 mg. All other study design features were the same, except for the exclusion of women of childbearing potential in the 2 fixed-dose studies. Exclusion of patients with marked personality disorders and depression meant that only 4 of the poor-outcome variables could be evaluated. RESULTS: Clinical improvement was similar for patients treated with sertraline whether or not they carried an agoraphobia diagnosis, had a duration of illness > 2 years, or were female. Patients with high baseline panic severity had significantly (p = .01) less improvement on the endpoint Clinical Global Impressions-Improvement (CGI-I) scale than patients with moderate severity, although the Clinical Global Impressions-Severity of Illness scale change score was higher in the patients with high severity (-2.00 vs. -1.31). For patients with 3 or more high-risk variables, there was a modest, but statistically significant, tendency for reduced global improvement (endpoint CGI-I score of 2.7 for the high-risk vs. 2.4 for the non-high-risk group; p = .017), although the high-risk group actually had a similar endpoint reduction in frequency of panic attacks (82%) compared with the non-high-risk group (78%). CONCLUSION: Treatment of panic disorder with sertraline was generally effective, even in the presence of baseline clinical variables that have been associated with poor treatment response. The main limitations of the analysis were the reliance on pooled data from 4 studies (even if the designs were similar) and our inability to examine the impact of depression and personality disorders on response to treatment because of the exclusion criteria of the clinical trials.

Inducing desorption of organic molecules with a scanning tunneling microscope: theory and experiments.

A scanning-tunneling microscope has been used to induce efficient local desorption of benzene from Si(100) at low currents (<100 pA), sample biases (approximately -2.4 V) and temperatures (22 K). A theoretical model based upon first principles electronic structure calculations and quantum mechanical wave packet dynamics describes this process as occurring via transient ionization of a pi state of the adsorbed molecule. This model accounts for the unexpected efficiency and sharp threshold of the yield.

Controlling organic reactions on silicon surfaces with a scanning tunneling microscope: theoretical and experimental studies of resonance-mediated desorption.

The dynamics of tip-induced, resonance-mediated bond-breaking in complex organic adsorbates is studied theoretically and experimentally. Desorption of benzene from a Si(100) surface is found to be efficient and sensitive to voltage, the measured yield rising from below 10(-10) to ca. 10(-6) per electron within a ca. 0.8 V range at low (< 100 pA) current. A theoretical model, based upon first principles electronic structure calculations and quantum mechanical wavepacket simulations, traces these observations to multi-mode dynamics triggered by a transition into a cationic resonance. The model is generalized to provide understanding of, and suggest a means of control over, the behaviour of different classes of organic adsorbates under tunneling current.

Absence of cardiovascular adverse effects of sertraline in children and adolescents.

OBJECTIVE: In a 12 week, placebo-controlled, parallel-design, multicenter study of sertraline for obsessive-compulsive disorder in 107 children and 80 adolescents, the authors prospectively assessed cardiovascular effects to doses of sertraline of < or = 200 mg/day. METHOD: Vital signs (blood pressure and heart rate) and electrocardiograph parameters (ECGs) were systematically evaluated at baseline and again throughout treatment. RESULTS: There were no clinically significant cardiovascular adverse events in any of the subjects enrolled in the study. Moreover, compared with baseline and placebo, sertraline treatment at an average dose of 167 mg did not result in any clinically meaningful changes in any ECG indices (PR, QRS, and QTc intervals), cardiac rhythm, blood pressure, or heart rate. CONCLUSIONS: These prospectively derived results support the cardiovascular safety of sertraline at doses up to 200 mg in children and adolescents.

Controlled molecular adsorption on silicon: laying a foundation for molecular devices.

This review is about understanding and controlling organic molecular adsorption on silicon. The goal is to provide a microscopic picture of structure and bonding in covalently attached molecule-silicon surface systems. The bias here is that an unprecedented, detailed understanding of adsorbate-surface structures is required in order to gain the control necessary to incorporate organic function into existing technologies or, eventually, to make new molecule-scale devices. A discussion of recent studies of adsorbate structure is presented. This includes simple alkenes, polyenes, benzene, and carene adsorbed on Si(100). Also included is a discussion of wet chemical procedures for forming alkyl and alkoxy covalently functionalized silicon. These discussions are presented together with comments on the related issues of adsorption dynamics and nano-scale manipulation in an effort to point the way toward principles and procedures that will allow the hybrid properties of organic molecules and surfaces to be harnessed.

Sertraline in the treatment of panic disorder. A multi-site, double-blind, placebo-controlled, fixed-dose investigation.

BACKGROUND: This study compared the efficacy and safety of sertraline to placebo in treating panic disorder. METHOD: 178 out-patients with panic disorder who exhibited at least four panic attacks during the four weeks prior to screening and three during the two weeks of lead-in were randomly assigned to 12 weeks of double-blind treatment with sertraline (50, 100 or 200 mg) or placebo. RESULTS: Sertraline was superior to placebo in reducing the number of panic attacks, situational attacks, unexpected attacks, limited symptom attacks, and time spent worrying (all P < 0.01) and the Hamilton Anxiety Scale (P < 0.05), although Clinical Global Impression (Improvement) did not significantly differentiate groups at 12 weeks and at end-point. No serious adverse events were associated with sertraline. No dose relationship was found for adverse events; overall drop-out rates were not different for sertraline or placebo, although more sertraline-treated subjects discontinued for adverse events, typically early in the study. Only dry mouth and ejaculation failure (primarily ejaculation delay) were associated significantly with sertraline. CONCLUSIONS: Sertraline was effective and safe in reducing panic attacks. Higher doses were no more effective than the 50 mg dose.

Sertraline in children and adolescents with obsessive-compulsive disorder: a multicenter randomized controlled trial.

CONTEXT: The serotonin reuptake inhibitors are the treatment of choice for patients with obsessive-compulsive disorder; however, empirical support for this assertion has been weaker for children and adolescents than for adults. OBJECTIVE: To evaluate the safety and efficacy of the selective serotonin reuptake inhibitor sertraline hydrochloride in children and adolescents with obsessive-compulsive disorder. DESIGN: Randomized, double-blind, placebo-controlled trial. PATIENTS: One hundred eighty-seven patients: 107 children aged 6 to 12 years and 80 adolescents aged 13 to 17 years randomized to receive either sertraline (53 children, 39 adolescents) or placebo (54 children, 41 adolescents). SETTING: Twelve US academic and community clinics with experience conducting randomized controlled trials. INTERVENTION: Sertraline hydrochloride was titrated to a maximum of 200 mg/d during the first 4 weeks of double-blind therapy, after which patients continued to receive this dosage of medication for 8 more weeks. Control patients received placebo. MAIN OUTCOME MEASURES: The Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS), the National Institute of Mental Health Global Obsessive Compulsive Scale (NIMH GOCS), and the NIMH Clinical Global Impressions of Severity of Illness (CGI-S) and Improvement (CGI-I) rating scales. RESULTS: In intent-to-treat analyses, patients treated with sertraline showed significantly greater improvement than did placebo-treated patients on the CY-BOCS (adjusted mean, -6.8vs -3.4, respectively; P=.005), the NIMH GOCS (-2.2 vs -1.3, respectively; P=.02), and the CGI-I (2.7 vs 3.3, respectively; P=.002) scales. Significant differences in efficacy between sertraline and placebo emerged at week 3 and persisted for the duration of the study. Based on CGI-I ratings at end point, 42% of patients receiving sertraline and 26% of patients receiving placebo were very much or much improved. Neither age nor sex predicted response to treatment. The incidence of insomnia, nausea, agitation, and tremor were significantly greater in patients receiving sertraline; 12 (13%) of 92 sertraline-treated patients and 3 (3.2%) of 95 placebo-treated patients discontinued prematurely because of adverse medical events (P=.02). No clinically meaningful abnormalities were apparent on vital sign determinations, laboratory findings, or electrocardiographic measurements. CONCLUSION: Sertraline appears to be a safe and effective short-term treatment for children and adolescents with obsessive-compulsive disorder.

Sertraline in the treatment of panic disorder: a flexible-dose multicenter trial.

BACKGROUND: The serotonin selective reuptake inhibitors are increasingly being used for the treatment of panic disorder. We examined the efficacy and safety of the serotonin selective reuptake inhibitor sertraline hydrochloride in patients with panic disorder. METHODS: One hundred seventy-six nondepressed outpatients with panic disorder, with or without agoraphobia, from 10 sites followed identical protocols that used a flexible-dose design. After 2 weeks of single-blind placebo, patients were randomly assigned to 10 weeks of double-blind, flexible-dose treatment with either sertraline hydrochloride (50-200 mg/d) or placebo. RESULTS: Sertraline-treated patients exhibited significantly greater improvement (P=.01) at end point than did patients treated with placebo for the primary outcome variable, panic attack frequency. Significant differences between groups were also evident for clinician and patient assessments of improvement as measured by the Clinical Global Impression Improvement (P=.01) and Severity (P=.009) Scales, Panic Disorder Severity Scale ratings (P=.03), high end-state function assessment (P=.03), Patient Global Evaluation rating (P=.01), and quality of life scores (P=.003). Adverse events, generally characterized as either mild or moderate, were not significantly different in overall incidence between the sertraline and placebo groups. CONCLUSION: Results support the safety and efficacy of sertraline for the short-term treatment of patients with panic disorder.

Sertraline in the treatment of panic disorder: a double-blind multicenter trial.

OBJECTIVE: This study determined the efficacy and safety of sertraline in the treatment of patients with panic disorder. METHOD: The study was a randomized, double-blind, parallel-group, flexible-dose comparison of sertraline and placebo in outpatients with a DSM-III-R diagnosis of panic disorder with or without agoraphobia. After a 2-week single-blind placebo lead-in, 168 patients entered a 10-week double-blind phase in which they were randomly assigned to treatment with either sertraline or placebo. RESULTS: Sertraline was significantly more effective than placebo in decreasing the number of full and limited-symptom panic attacks. Among patients who completed the study, the mean number of panic attacks per week dropped by 88% in the sertraline-treated patients and 53% in the placebo-treated patients. Sertraline-treated patients also had significantly more improvement than placebo-treated patients in scores on the Quality of Life Enjoyment and Satisfaction Questionnaire, patient global evaluation, and Clinical Global Impression severity of illness and global improvement scales. Overall, patients tolerated sertraline well, and only 9% terminated treatment because of side effects. CONCLUSIONS: Sertraline is an effective and well-tolerated treatment for patients with panic disorder.

Methodologies and outcomes from the sertraline multicenter flexible-dose trials.

This article summarizes the results of a combined analysis from two identical multicenter clinical trials that investigated the efficacy and safety of sertraline versus placebo for treating panic disorder. Patients with panic disorder who were treated with sertraline had a statistically significant reduction in the mean number of panic attacks per week (the primary efficacy measure) as compared with placebo (4.8 vs. 2.5, p < .001). Sertraline-treated patients also showed greater improvement that was statistically significant on several ratings of panic disorder symptomatology and functioning. The design characteristics, clinical rating measures, and outcome measures in these trials included most of the features deemed essential by Shear and Maser (1994) in their summary of the NIMH Consensus Conference for the development of standardized assessments for panic disorder. This suggests that the NIMH Consensus Conference played a key role in developing successful multicenter pharmacological treatment studies, such as this one that ultimately demonstrated that sertraline was an effective treatment for panic disorder.

Sertraline treatment of children and adolescents with obsessive-compulsive disorder or depression: pharmacokinetics, tolerability, and efficacy.

OBJECTIVE: To evaluate the pharmacokinetics, safety, and efficacy of sertraline in children (6 to 12 years old) and adolescents (13 to 17 years old). METHOD: Children (n = 29) and adolescents (n = 32) with major depression, obsessive-compulsive disorder (OCD), or both received a single dose of 50 mg of sertraline followed, 1 week later, by 35 days of sertraline treatment as follows: (1) either a starting dose of 25 mg/day titrated to 200 mg/day in 25-mg increments or (2) a starting dose of 50 mg/day titrated to 200 mg/day in 50-mg increments. Sertraline and desmethylsertraline pharmacokinetics were determined approximately weekly, and efficacy measures were assessed before drug administration and at the end of treatment. RESULTS: Mean area under the plasma concentration-time curve (AUC), peak plasma concentration (Cmax), and elimination half-life (t1/2) for sertraline and desmethylsertraline were similar to previously reported adult values. No titration-dependent pharmacokinetic or safety differences were seen. While Cmax and AUC0-24 were greater for children versus adolescents, these differences disappeared after parameters were normalized for body weight. Sertraline was well tolerated in both children and adolescents, with adverse experiences similar to those previously reported by adult patients. Efficacy measurements indicated improvement (p < .001) in depression and OCD symptomatology. CONCLUSIONS: Sertraline can be safely administered to pediatric patients using the currently recommended adult titration schedule.