Predictors of lapse in first week of smoking abstinence in PTSD and non-PTSD smokers

INTRODUCTION

Retrospective research suggests smokers with posttraumatic stress disorder (PTSD) lapse more quickly after their quit date. Ecological momentary assessment (EMA) research is needed to confirm the presence of early smoking lapse in PTSD and form conceptualizations that inform intervention.

METHODS

Smokers with (n = 55) and without (n = 52) PTSD completed alarm-prompted EMA of situational and psychiatric variables the week before and after a quit date, and self-initiated EMA following smoking lapses. Blood samples at baseline and on the quit date allowed assessment of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEA(S)).

RESULTS

PTSD was related to shorter time to lapse (hazard ratio [HR] = 1.677, 95% CI: 1.106-2.544). Increased smoking abstinence self-efficacy was related to longer time to lapse (HR = 0.608, 95% CI: 0.430-0.860). Analyses of participants' real-time reports revealed that smokers with PTSD were more likely to attribute first-time lapses to negative affect ( = 5.412, p = .020), and trauma reminders (Fisher's exact p = .003**). Finally, the quit date decrease in DHEA(S) was related to shorter time to lapse (HR = 1.009, 95% CI: 1.000-1.018, p < .05).

CONCLUSIONS

Results provide evidence of shorter time to first smoking lapse in PTSD, and add to evidence that early lapse occasions are more strongly related to trauma reminders, negative affect, and cravings in smokers with PTSD.

Consumer perspectives on genetic testing for psychiatric disorders: the attitudes of veterans with posttraumatic stress disorder and their families

The perspectives of patients with posttraumatic stress disorder (PTSD) on genetic research have not yet been investigated in the genetics research literature. To provide a basis for research on attitudes toward genetic research in PTSD, we surveyed the U.S. Military Afghanistan/Iraq-era veterans with PTSD and their social support companions to investigate the attitudes and knowledge about genetics and genetic testing. One hundred forty-six veterans (76 with PTSD and 70 without PTSD) participated in this study. Each veteran participant had a corresponding companion (primarily spouses, but also relatives and friends) who they identified as a primary member of their social support network. Participants and companions completed self-report measures on knowledge of genetics and attitudes toward genetic testing for PTSD. Results indicated that, relative to veterans without PTSD, veterans with PTSD had similar levels of genetic knowledge, but less-favorable attitudes toward genetic testing. Differences persisted after controlling for age and genetics knowledge. No differences between companions of those with and without PTSD were observed. Results suggest that the perspective of those with PTSD regarding genetic testing is in need of further investigation, especially if potentially beneficial genetic testing for PTSD is to be utilized in the target population.

An examination of general aggression and intimate partner violence in women with posttraumatic stress disorder

Research has documented significant relationships between posttraumatic stress disorder (PTSD), aggression, and intimate partner violence (IPV). Most of these studies have focused on men and measured violence by self-report. This study examined (a) the association between PTSD and general aggression among women, (b) the association between IPV and PTSD among married and/or cohabitating couples, and (c) the concordance between self and collateral reports of IPV. One hundred twenty participants provided information about PTSD symptoms and general aggression toward others, and 43 married and/or cohabitating couples provided information about PTSD and IPV. Women with PTSD reported more general aggression, IPV perpetration, and IPV victimization. Collateral informants of those with and without PTSD did not differ significantly in their report of IPV. Concordance between participants and spouses or partners was low to moderate. These results are discussed within the context of extant IPV literature.

Assessing the role of attention-deficit/hyperactivity disorder symptoms in smokers with and without posttraumatic stress disorder

INTRODUCTION

Smoking prevalence among individuals with posttraumatic stress disorder (PTSD) is elevated relative to non-PTSD smokers, and there is evidence to suggest that affect regulation may be a motivation for smoking among those with this disorder. Previous studies have also indicated that (a) PTSD is frequently comorbid with attention-deficit/hyperactivity disorder (ADHD), (b) individuals with ADHD smoke at significantly higher rates than the general population, (c) subclinical ADHD symptoms are a risk factor for smoking, and (d) affect regulation is a motivation for smoking in ADHD. The goal of this study was to assess the degree to which ADHD symptoms were uniquely associated with smoking-related affective functioning (SRAF) variables above and beyond the variance already explained by PTSD symptoms.

METHODS

Smokers with (n = 55) and without PTSD (n = 68) completed measures assessing PTSD symptoms, ADHD symptoms, and SRAF.

RESULTS

The PTSD group endorsed significantly more severe levels of DSM-IV inattentive and hyperactive-impulsive ADHD symptoms. A series of hierarchical regressions among the entire sample indicated that, after accounting for PTSD symptoms, ADHD symptoms were associated with lower positive affect, higher negative affect, higher emotion dysregulation, higher anxiety sensitivity, and higher urges to smoke to increase positive affect.

CONCLUSIONS

Taken together, these findings suggest that ADHD symptoms may increase affective dysregulation difficulties already faced by smokers, particularly those with PTSD, which may, in turn, confer increased risk for smoking relapse in those with higher levels of symptomatology of both disorders.

Autobiographical memory for stressful events: the role of autobiographical memory in posttraumatic stress disorder

To provide the three-way comparisons needed to test existing theories, we compared (1) most-stressful memories to other memories and (2) involuntary to voluntary memories (3) in 75 community dwelling adults with and 42 without a current diagnosis of posttraumatic stress disorder (PTSD). Each rated their three most-stressful, three most-positive, seven most-important and 15 word-cued autobiographical memories, and completed tests of personality and mood. Involuntary memories were then recorded and rated as they occurred for 2 weeks. Standard mechanisms of cognition and affect applied to extreme events accounted for the properties of stressful memories. Involuntary memories had greater emotional intensity than voluntary memories, but were not more frequently related to traumatic events. The emotional intensity, rehearsal, and centrality to the life story of both voluntary and involuntary memories, rather than incoherence of voluntary traumatic memories and enhanced availability of involuntary traumatic memories, were the properties of autobiographical memories associated with PTSD.

Exploration of the resilience construct in posttraumatic stress disorder severity and functional correlates in military combat veterans who have served since September 11, 2001

OBJECTIVE

This study evaluated the relationship between resilience and psychological functioning in military veterans deployed to a region of military conflict in support of Operation Enduring Freedom or Operation Iraqi Freedom.

METHOD

497 military veterans completed a structured psychiatric interview and questionnaires measuring psychological symptoms, resiliency, and trauma exposure. The study had 2 primary aims: (1) to examine whether the association between trauma exposure and PTSD was moderated by resilience and (2) to examine whether resilience was uniquely associated with functional outcomes after accounting for PTSD. Measures included the Structured Clinical Interview for DSM-IV-TR Axis I Disorders (for PTSD diagnosis), the Connor-Davidson Resilience Scale, and the Traumatic Life Events Questionnaire. Data were collected between June 2005 and February 2009.

RESULTS

Evaluating the association of resilience and trauma exposure with PTSD revealed main effects for combat exposure, lifetime trauma exposure, and resilience. Additionally, there was a significant (P < .05) interaction between combat exposure and resilience such that higher levels of resilience were particularly protective among individuals with high combat exposure. After controlling for age, gender, minority status, trauma exposure, and PTSD diagnosis, resilience was uniquely associated with decreased suicidality, reduced alcohol problems, lower depressive symptom severity, and fewer current health complaints and lifetime and past-year medical problems.

CONCLUSIONS

These results suggest that resilience is a construct that may play a unique role in the occurrence of PTSD and severity of other functional correlates among deployed veterans. Future studies in this area would benefit from a prospective design, the evaluation of other possible protective processes (e.g., social support), and specific examination of particular aspects of resilience and how resilience may be increased.

Prospective study of externalizing and internalizing subtypes of posttraumatic stress disorder and their relationship to mortality among Vietnam veterans

Posttraumatic stress disorder (PTSD) can be a complex disorder, and some studies have found that samples of individuals with PTSD contain subtypes that may relate to health outcomes. The goals were to replicate previously identified PTSD subtypes and examine how subtype membership relates to mortality. Data from the Vietnam Experience Study and a clinical sample of Vietnam veterans were combined (n = 5248) to address these research questions. Consistent with previous studies, 3 PTSD subtypes emerged: externalizers (n = 317), internalizers (n = 579), and low pathology (n = 280). Posttraumatic stress disorder diagnosis was associated with increased risk of all-cause and behavioral-cause (eg, homicide, suicide) mortality. Both externalizing and internalizing subtypes had higher mortality and were more likely to die from cardiovascular causes than those without PTSD. Externalizers were more likely to die from substance-related causes than those without PTSD. The value of considering possible PTSD subtypes is significant in that it may contribute to identifying more specific targets for treatment and rehabilitation in veterans with PTSD.

Effects of posttraumatic stress disorder status and covert hostility on cardiovascular responses to relived anger in women with and without PTSD

Previous literature has found greater heart rate (HR) and blood pressure (BP) responses during relived anger, and a positive association between covert hostility and relived anger, in male veterans with posttraumatic stress disorder (PTSD). This study investigated hostility and cardiovascular responses to a relived anger task in 120 women (70 with PTSD and 50 without PTSD). Women with PTSD reported greater hostile beliefs and covert hostility than non-PTSD controls, reported greater anger and anxiety during the anger recall task, and had higher resting HR. In general, the relationship between PTSD and cardiovascular response was moderated by covert hostility, which was associated with greater baseline diastolic BP and greater HR during relived anger and anger recovery among women with PTSD, but not among non-PTSD controls. Results suggest that the relationship between PTSD and cardiovascular response is moderated by hostility.

Evaluation of lifetime trauma exposure and physical health in women with posttraumatic stress disorder or major depressive disorder

The current study examines lifetime trauma exposure rates in 148 women with posttraumatic stress disorder (PTSD), major depressive disorder (MDD), or neither diagnosis and whether this is related to measures of PTSD, depression, hostility, health symptoms, and health care utilization. Findings indicate that multiple trauma exposures were prevalent in this sample, with 96% of those with PTSD and 79% of those with MDD reporting three or more trauma exposures compared to 46% in the comparison group. Controlling for diagnostic status, regression analysis for PTSD symptom severity reveals that the trauma exposure adult physical assault category was significantly associated with more severe PTSD and depressive symptoms, whereas the childhood violence category was most associated with increased hostility. PTSD and MDD groups reported greater past year health conditions and health care utilization.

Self-reported health and physician diagnosed illnesses in women with posttraumatic stress disorder and major depressive disorder

Posttraumatic stress disorder has been associated with poor physical health. Depression is also associated with poor health, and may be responsible for the apparent relationship between PTSD and health outcomes. The current study examined self-reported and physician diagnosed medical morbidity in women. Women with PTSD alone were compared to three other groups of women: women with PTSD and comorbid major depressive disorder (MDD), women with MDD only, or women with neither diagnosis (comparison group). Results suggest that PTSD, with or without MDD, is associated with poor health in women. Posttraumatic stress disorder severity was related to health complaints beyond the effects of both somatization and depressive symptoms among women with PTSD. Findings and implications are discussed in relation to previous research in the area.

Ambulatory cardiovascular activity and hostility ratings in women with chronic posttraumatic stress disorder

BACKGROUND

The objective of the current study is to evaluate the relationship between hostility and ambulatory cardiovascular activity in women with and without posttraumatic stress disorder (PTSD).

METHODS

One hundred and one women completed 24 hours of ambulatory monitoring and standardized diagnostic and hostility measures. Generalized estimating equations analysis was used to examine the effects of group and hostility factor scores (hostile beliefs, overt hostility, and covert hostility) on ambulatory heart rate (AHR) and ambulatory systolic (ASBP) and diastolic (ADBP) blood pressure.

RESULTS

After controlling for covariates, there was an interaction between PTSD and both hostile beliefs and overt hostility for AHR. Increases in hostility were associated with greater increases in heart rate among women with PTSD relative to those without PTSD. There was a similar interaction between hostile beliefs and group for ADBP.

CONCLUSIONS

Increased AHR and blood pressure have been linked to poor cardiovascular outcomes in nonpsychiatric populations. Individuals with PTSD display increased hostility, a construct that has also been linked to poorer cardiovascular outcomes. Increases in hostile beliefs were associated with a greater increase in ADBP among women with PTSD as compared with control subjects. These data suggest that PTSD might in part moderate the relationship between hostility and cardiovascular outcomes.

Influences of Comorbid Disorders on Personality Assessment Inventory Profiles in Women with Posttraumatic Stress Disorder

The present study describes Personality Assessment Inventory (PAI) profiles for women with posttraumatic stress disorder (PTSD). Four groups of women were sampled: single Axis I diagnosis of PTSD; PTSD and major depressive disorder (MDD); PTSD, MDD, at least one other Axis I disorder; and controls with no Axis I disorder. Higher comorbidity rates were associated with higher mean profile elevations and broader range of endorsed symptoms. The group with the highest rate of comorbidity produced profiles most similar to previously published reports of patients with PTSD. This is in contrast to women with a single diagnosis of PTSD, who produced relative mean elevations only on subscales measuring distress caused by trauma and physiological symptoms of depression. Thus, published profiles may be more reflective of PTSD with comorbidity than a single diagnosis of PTSD.

Smoking in help-seeking veterans with PTSD returning from Afghanistan and Iraq

Past research has shown that veterans and individuals with posttraumatic stress disorder (PTSD) have increased rates of smoking. However, the rates of smoking in younger help-seeking veterans returning from Afghanistan and Iraq, and possible correlates of smoking among this population are unknown. In this study, we evaluated the rate of lifetime and current smoking among a sample of 90 returning male veterans diagnosed with PTSD. Fifty-nine percent reported a lifetime history of smoking including 32% that were current smokers. Current smokers were significantly younger than non-smokers. Current smokers (mean age=31) reported a mean age of smoking onset as 15.86 with a pack year history of 8.89. These smokers reported on average five previous quit attempts. According to a stages of change model, one-half of the smokers were in the contemplation phase of stopping smoking (50%), 29% were in the pre-contemplation phase and 21% were in the preparation phase. The results are placed in the context of non-psychiatric and psychiatric smokers.

Self-mutilative behaviors in male veterans with posttraumatic stress disorder

Self-mutilative behaviors (SMB) were examined in a sample of male veterans with posttraumatic stress disorder (PTSD). The primary objective was to determine the prevalence of SMB and any physical, cognitive, or affective antecedents and correlates for these behaviors. Participants included 509 male veterans with PTSD and levels of PTSD, depression, alcohol use, hostility, and impulsivity were evaluated to determine if these variables were related to SMB. Antecedents and sequelae of SMB were also examined to generate hypotheses regarding the functions of these behaviors. A second type of habit behavior, body-focused repetitive behaviors (BFRB), was also examined as part of the study. Findings indicated that veterans who engaged in either type of habit behavior were younger than those who did not engage in SMB or BFRB. Veterans reporting SMB also reported higher levels of PTSD, depression, hostility, and impulsivity compared to the BFRB and no-habit groups. Examination of habit antecedents and sequelae showed support for the automatic-positive reinforcement function of SMB. These findings are discussed in the context of research and treatment involving male veterans with PTSD who engage in SMB.

Gender differences in immediate antecedents of ad lib cigarette smoking in smokers with and without posttraumatic stress disorder: a preliminary report

Using ambulatory methods for monitoring, this study investigated gender differences regarding the association between smoking and situational cues in 63 smokers with posttraumatic stress disorder (PTSD) and 32 smokers without PTSD. Smokers were instructed to complete a diary entry each time an ambulatory blood pressure monitor took a reading and each time they prepared to smoke. Generalized estimating equations contrasted 682 smoking and 444 nonsmoking situations by group status. For all smokers, ad lib smoking was strongly related to craving. For women with PTSD, ad lib smoking was strongly related to total PTSD symptoms, PTSD reexperiencing symptoms, and PTSD hyperarousal symptoms. For men with PTSD, ad lib smoking was significantly related to negative affect, PTSD reexperiencing symptoms, restlessness, and worry. No other mood antecedents were significant for women or men smokers without PTSD. These results are consistent with previous studies documenting gender differences in smoking behavior, and underscore the importance of examining gender differences in psychiatric samples.

Objective evidence of sleep disturbance in women with posttraumatic stress disorder

Although sleep disturbance is considered a hallmark of posttraumatic stress disorder (PTSD), objective evidence for sleep disturbance in patients with PTSD has been equivocal. The goal of the current investigation was to objectively examine sleep disturbance among women with PTSD in their home environment. Women with PTSD (n = 30) and a control group (n = 22) completed three nights of actigraphy monitoring. Results from actigraphy indicated that women with PTSD had poorer sleep efficiency, increased sleep latency, and more restless sleep. Actigraphy measures were moderately correlated with self-report sleep-log data, but were unrelated to scores on the Pittsburgh Sleep Quality Index. The current study provides evidence that women with PTSD have objectively measured sleep disturbance in their normal environment at home. Disturbed sleep may have important implications for the health and well-being of individuals with PTSD.

The effects of cigarette smoking on script-driven imagery in smokers with and without posttraumatic stress disorder

The study investigated the effects of smoking a nicotinized or denicotinized cigarette on craving, affect and posttraumatic stress disorder (PTSD) symptoms while recalling neutral, stressful and traumatic events in smokers with and without PTSD. Smokers completed laboratory sessions during which they were presented with audiotapes of personalized scripts followed by smoking a cigarette. The effect of the script and cigarette conditions on dependent variables was evaluated. There was a main effect of script type across groups for smoking craving, negative affect and PTSD symptoms, with increased symptoms in trauma and stressful conditions. Responses were significantly higher in PTSD smokers. Smoking either cigarette type resulted in decreased craving, negative affect and PTSD symptoms in both groups. A second script presentation following smoking elicited similar responses, suggesting the ameliorative effect of having smoked a cigarette was short-lived. These results support that context and non-pharmacologic effects of smoking are important variables in smoking craving and mood, particularly in smokers with PTSD.

Baroreceptor sensitivity at rest and during stress in women with posttraumatic stress disorder or major depressive disorder

The relationship between posttraumatic stress disorder (PTSD) and parasympathetic nervous system functioning was investigated during a baseline rest period and anger recall speaking task using noninvasive estimates of baroreceptor sensitivity. Participants (N = 124) were women categorized into one of four diagnostic groups: PTSD without major depressive disorder (MDD), PTSD with comorbid MDD, MDD without PTSD, and controls with neither psychiatric diagnosis. Women with PTSD (with or without MDD) exhibited significantly lower resting baroreceptor sensitivity than women not diagnosed with PTSD. Baroreceptor sensitivity decreased during the anger recall task, and the decrease was less among the psychiatric groups. Taken together, these findings suggest that PTSD is associated with reduced parasympathetic nervous system functioning.

Emotional reactivity to trauma stimuli and duration of past smoking cessation attempts in smokers with posttraumatic stress disorder

The present study examined whether reactivity to emotional stressors is related to early relapse from smoking cessation in persons with posttraumatic stress disorder (PTSD). Smokers with PTSD who had failed to sustain any previous quit attempt for 7 days (n=26) and PTSD smokers who were able to sustain a quit attempt for more than a week (n=50) were exposed to emotional stimuli in the form of personalized scripts that included neutral/relaxing experiences, stressful/nontraumatic experiences, and traumatic experiences. Results indicated an interaction between script type and group. Although groups did not differ after presentation of neutral scripts, persons with PTSD unable to sustain a quit attempt for as long as 7 days responded with greater levels of emotional reactivity to both stressful and trauma stimuli relative to those able to sustain a quit attempt longer than 7 days. Further, results suggested that emotional reactivity to stressors (both traumatic and nontraumatic) is related to duration of past longest quit attempt in smokers with PTSD. Results are consistent with findings in nonpsychiatric samples that suggest that individual differences in affective regulatory processes are related to duration of smoking cessation attempts. Systematic replications including a prospective design are recommended.

A placebo-controlled trial of bupropion SR in the treatment of chronic posttraumatic stress disorder

OBJECTIVE

Although selective serotonin reuptake inhibitors have been the most empirically studied pharmacotherapy for posttraumatic stress disorder (PTSD), a need remains for the investigation of additional pharmacological agents in the treatment of PTSD. The present study examined the use of bupropion sustained release (SR) as compared with placebo for symptom reduction in patients with PTSD: approximately half who were already prescribed an selective serotonin reuptake inhibitor and half who were not.

METHOD

Thirty patients (mean age, 50 years) with civilian- or military-related PTSD enrolled in an 8-week evaluation of bupropion SR versus placebo assigned in a 2:1 ratio in addition to their usual pharmacological care. Statistical tests included analyzing both study completers and using an intent-to-treat analysis, as well as post hoc examination of responders versus nonresponders.

RESULTS

Although no between-group differences were detected, both groups reported a reduction in PTSD symptoms. In a hypothesis-generating post hoc analysis of responders versus nonresponders in the bupropion SR condition (defined as a Clinician Global Improvement score of at least minimally improved), it seemed that younger patients not currently on another antidepressant were more likely to benefit from bupropion.

CONCLUSIONS

Bupropion SR in the treatment of PTSD had no significant effect in the current sample. Factors contributing to the absence of an effect need further study. Our analysis points to the inclusion of age and concomitant antidepressant treatment as important variables in any future larger-scale study.

Combretastatin A-4 phosphate as a tumor vascular-targeting agent: early effects in tumors and normal tissues

The potential for tumor vascular-targeting by using the tubulin destabilizing agent disodium combretastatin A-4 3-0-phosphate (CA-4-P) was assessed in a rat system. This approach aims to shut down the established tumor vasculature, leading to the development of extensive tumor cell necrosis. The early vascular effects of CA-4-P were assessed in the s.c. implanted P22 carcinosarcoma and in a range of normal tissues. Blood flow was measured by the uptake of radiolabeled iodoantipyrine, and quantitative autoradiography was used to measure spatial heterogeneity of blood flow in tumor sections. CA-4-P (100 mg/kg i.p.) caused a significant increase in mean arterial blood pressure at 1 and 6 h after treatment and a very large decrease in tumor blood flow, which-by 6 h-was reduced approximately 100-fold. The spleen was the most affected normal tissue with a 7-fold reduction in blood flow at 6 h. Calculations of vascular resistance revealed some vascular changes in the heart and kidney for which there were no significant changes in blood flow. Quantitative autoradiography showed that CA-4-P increased the spatial heterogeneity in tumor blood flow. The drug affected peripheral tumor regions less than central regions. Administration of CA-4-P (30 mg/kg) in the presence of the nitric oxide synthase inhibitor, N(omega)-nitro-L-arginine methyl ester, potentiated the effect of CA-4-P in tumor tissue. The combination increased tumor vascular resistance 300-fold compared with less than 7-fold for any of the normal tissues. This shows that tissue production of nitric oxide protects against the damaging vascular effects of CA-4-P. Significant changes in tumor vascular resistance could also be obtained in isolated tumor perfusions using a cell-free perfusate, although the changes were much less than those observed in vivo. This shows that the action of CA-4-P includes mechanisms other than those involving red cell viscosity, intravascular coagulation, and neutrophil adhesion. The uptake of CA-4-P and combretastatin A-4 (CA-4) was more efficient in tumor than in skeletal muscle tissue and dephosphorylation of CA-4-P to CA-4 was faster in the former. These results are promising for the use of CA-4-P as a tumor vascular-targeting agent.

Peroxidase-catalyzed effects of indole-3-acetic acid and analogues on lipid membranes, DNA, and mammalian cells in vitro

This study aimed to explore the mechanisms and molecular parameters which control the cytotoxicity of derivatives of indole-3-acetic acid (IAA) when oxidatively activated by horseradish peroxidase (HRP). Lipid peroxidation was measured in liposomes, damage to supercoiled plasmid DNA assessed by gel electrophoresis, free radical intermediates detected by EPR following spin trapping, binding of IAA-derived products demonstrated by 3H labelling, stable products measured by HPLC, and cytotoxicity in hamster fibroblasts measured by clonogenic survival. IAA, and nine analogues more easily oxidized by HRP, caused lipid peroxidation in liposomes, but not detectably in membranes of hamster fibroblasts, and were cytotoxic after HRP activation to varying degrees. Cytotoxicity was not correlated with activation rate. The hydrophilic vitamin E analogue, Trolox, inhibited cytotoxicity, whereas loading fibroblasts with vitamin E was ineffective, consistent with an oxidative mechanism in which radical precursors to damage are intercepted by Trolox in the aqueous phase. However, two known oxidation products were nontoxic (the 3-carbinol and 3-aldehyde, both probably produced from 3-CH2OO* peroxyl radicals via the 3-CH*2 [skatolyl] radical following decarboxylation of the radical cation). The skatolyl radical from IAA was shown by EPR with spin trapping to react with DNA; electrophoresis showed binding to occur. Treatment of hamster fibroblasts with 5-3H-IAA/HRP resulted in intracellular bound 3H. Together with earlier results, the new data point to unknown electrophilic oxidation products, reactive towards intracellular targets, being involved in cytotoxicity of the IAA/HRP combination, rather than direct attack of free radicals, excited states, or membrane lipid peroxidation.

Determination of combretastatin A-4 and its phosphate ester pro-drug in plasma by high-performance liquid chromatography

High-performance liquid chromatography with both absorbance and fluorescence detection has been applied to the determination of the potential anti-tumour agent combretastatin A-4 and its phosphate ester in murine and human plasma. The presence of different interfering peaks in the two species makes absorbance detection at 295 nm the method of choice for the mouse, and fluorescence detection (295 nm/390 nm) for human plasma. The calibration was linear over the range studied (0.01-50 microM for combretastatin A-4, 0.02-200 microM for combretastatin A-4 phosphate), with quantitation limits of 0.05 microM for both drugs in the mouse, and 0.05 microM and 0.0125 microM for the phosphate ester and free drug, respectively, in human plasma. The method should be useful for pharmacokinetic studies in the forthcoming Phase I clinical trial of combretastatin A-4 phosphate.

Pharmacokinetics of nicotinamide in cancer patients treated with accelerated radiotherapy: the experience of the Co-operative Group of Radiotherapy of the European Organization for Research and Treatment of Cancer

BACKGROUND

The EORTC has initiated studies to combine nicotinamide with carbogen in accelerated fractionation schedules (ARCON), since for some tumour types, acute and chronic hypoxia as well as treatment protraction may prejudice the outcome of radiotherapy. The tolerable dose of nicotinamide and the optimal interval for administration need to be ascertained.

AIM

Full pharmacokinetic profiles of nicotinamide concentrations in plasma were analyzed repeatedly in 15 patients to determine the inter- and intra-patient variability in peak plasma concentrations and the optimum times for administering nicotinamide as a radiosensitizer.

METHODS

Nicotinamide (Nicobion) was administered in tablet form to patients with advanced head and neck and non-small cell lung carcinomas. A standard 6 g dose was given regardless of body weight after an overnight fast and at least 30 min before breakfast. In 15 patients, blood samples were taken prior to and 1, 2, 4, 6, 8, 12 and 24 h after administration of the drug. This full profile was determined on two to four occasions for the head and neck cancer patients and on two occasions for the lung cancer patients. For each profile, the maximum concentration of nicotinamide (Cmax), time to peak plasma concentration (Tmax), elimination half-lives (t1/2) and area under the curve (AUC) were determined. Compliance was recorded and nausea and vomiting were graded on a 0-3 scale. Complete profiles of the five major metabolites were also obtained.

RESULTS

In the 48 complete sets of blood samples, peak plasma concentrations ranged from 787 to 2312 nmol/ml with a median value of 1166 nmol/ml. The peak plasma concentration was achieved at 1 h in only 54% of the pharmacokinetic profiles, but at this time 92% of the profiles had already exceeded the target concentration of 700 nmol/ml, the level required in the mouse for tumour radiosensitization. The median t1/2 for all 15 cases was 9.3 h, with minimum and maximum values of 4.2 and 26.8 h. The highest concentrations of nicotinamide metabolites were found to be the N-oxide, 2-pyridone and 1-methylnicotinamide. The toxicity (nausea and vomiting) was scored and found not to be correlated with any of the pharmacokinetic parameters.

CONCLUSIONS

The plasma concentrations considered necessary to radiosensitize can easily be exceeded with a dose of 6 g taken as 12 x 500 mg in tablet form; 700 nmol/ml was achieved in all patients and apparently would have been achieved in most even with a considerable reduction in dose. An adequate time between administration and radiotherapy appeared to be 1 h with this drug formulation for 92% of the profiles.

Indolequinone antitumor agents: reductive activation and elimination from (5-methoxy-1-methyl-4,7-dioxoindol-3-yl)methyl derivatives and hypoxia-selective cytotoxicity in vitro

A series of indolequinones bearing a variety of leaving groups at the (indol-3-yl)methyl position was synthesized by functionalization of the corresponding 3-(hydroxymethyl)indolequinone, and the resulting compounds were evaluated in vitro as bioreductively activated cytotoxins. The elimination of a range of functional groups-carboxylate, phenol, and thiol-was demonstrated upon reductive activation under both chemical and quantitative radiolytic conditions. Only those compounds which eliminated such groups under both sets of conditions exhibited significant hypoxia selectivity, with anoxic:oxic toxicity ratios in the range 10-200. With the exception of the 3-hydroxymethyl derivative, radiolytic generation of semiquinone radicals and HPLC analysis indicated that efficient elimination of the leaving group occurred following one-electron reduction of the parent compound. The active species in leaving group elimination was predominantly the hydroquinone rather than the semiquinone radical. The resulting iminium derivative acted as an alkylating agent and was efficiently trapped by added thiol following chemical reduction and by either water or 2-propanol following radiolytic reduction. A chain reaction in the radical-initiated reduction of these indolequinones (not seen in a simpler benzoquinone) in the presence of a hydrogen donor (2-propanol) was observed. Compounds that were unsubstituted at C-2 were found to be up to 300 times more potent as cytotoxins than their 2-alkyl-substituted analogues in V79-379A cells, but with lower hypoxic cytotoxicity ratios.