Prevalence of mental health problems and functional impairment among active component and National Guard soldiers 3 and 12 months following combat in Iraq

CONTEXT

A growing body of literature has demonstrated the association of combat in Iraq and Afghanistan with postdeployment mental health problems, particularly posttraumatic stress disorder (PTSD) and depression. However, studies have shown varying prevalence rates of these disorders based on different case definitions and have not assessed functional impairment, alcohol misuse, or aggressive behavior as comorbid factors occurring with PTSD and depression.

OBJECTIVES

To (1) examine the prevalence rates of depression and PTSD using several case definitions including functional impairment, (2) determine the comorbidity of alcohol misuse or aggressive behaviors with depression or PTSD, and (3) compare rates between Active Component and National Guard soldiers at the 3- and 12-month time points following their deployment to Iraq.

DESIGN

Population-based, cross-sectional study.

SETTING

United States Army posts and National Guard armories.

PARTICIPANTS

A total of 18 305 US Army soldiers from 4 Active Component and 2 National Guard infantry brigade combat teams.

INTERVENTIONS

Between 2004 and 2007, anonymous mental health surveys were collected at 3 and 12 months following deployment.

MAIN OUTCOME MEASURES

Current PTSD, depression, functional impairment, alcohol misuse, and aggressive behavior.

RESULTS

Prevalence rates for PTSD or depression with serious functional impairment ranged between 8.5% and 14.0%, with some impairment between 23.2% and 31.1%. Alcohol misuse or aggressive behavior comorbidity was present in approximately half of the cases. Rates remained stable for the Active Component soldiers but increased across all case definitions from the 3- to 12-month time point for National Guard soldiers.

CONCLUSIONS

The prevalence rates of PTSD and depression after returning from combat ranged from 9% to 31% depending on the level of functional impairment reported. The high comorbidity with alcohol misuse and aggression highlights the need for comprehensive postdeployment screening. Persistent or increased prevalence rates at 12 months compared with 3 months postdeployment illustrate the persistent effects of war zone service and provide important data to guide postdeployment care.

Stigma, barriers to care, and use of mental health services among active duty and National Guard soldiers after combat

OBJECTIVE

This study examined rates of utilization of mental health care among active duty and National Guard soldiers with mental health problems three and 12 months after they returned from combat in Iraq. Stigma and barriers to care were also reported for each component (active duty and National Guard).

METHODS

Cross-sectional, anonymous surveys were administered to 10,386 soldiers across both time points and components. Mean scores from 11 items measuring stigma and barriers to care were computed. Service utilization was assessed by asking soldiers whether they had received services for a mental health problem from a mental health professional, a medical doctor, or the Department of Veterans Affairs in the past month. Risk of mental problems was measured using the Patient Health Questionnaire, the PTSD Checklist, and items asking about aggressive behaviors and "stress, emotional, alcohol, or family" problems within the past month.

RESULTS

A higher proportion of active duty soldiers than National Guard soldiers reported at least one type of mental health problem at both three months (45% versus 33%) and 12 months (44% versus 35%) postdeployment. Among soldiers with mental health problems, National Guard soldiers reported significantly higher rates of mental health care utilization 12 months after deployment, compared with active duty soldiers (27% versus 13%). Mean stigma scores were higher among active duty soldiers than among National Guard soldiers.

CONCLUSIONS

Active duty soldiers with a mental health problem had significantly lower rates of service utilization than National Guard soldiers and significantly higher endorsements of stigma. Current and future efforts to improve care for veterans should work toward reducing the stigma of receiving mental health care.

Screening for alcohol misuse and alcohol-related behaviors among combat veterans

OBJECTIVE

The U.S. military conducts health screenings of service members three to six months after they return from combat deployments. This population health program includes a modified version of the Two-Item Conjoint Screen (TICS), which is widely used in primary care to screen for alcohol misuse. Rates of referral in the military for alcohol treatment are very low, and the utility of these screening questions in predicting serious alcohol-related behaviors is unknown.

METHODS

Anonymous surveys were collected from 6,527 U.S. Army soldiers who were screened three to four months after returning from deployment to Iraq. Positive responses on the TICS alcohol screen were correlated with alcohol-related behaviors. Odds ratios (ORs) were calculated using logistic regression, after adjusting for gender, rank, race, and military component (active or reserve).

RESULTS

Twenty-seven percent of soldiers screened positive for alcohol misuse. Compared with soldiers who screened negative, those who screened positive were more likely to have recently engaged in the following behaviors: drinking and driving (OR=4.99, 95% confidence interval [CI]=4.31-5.76), riding with a driver who had been drinking (OR=5.87, CI=4.99-6.91), reporting late or missing work because of a hangover (OR=9.24, CI=6.73-12.68), using illicit drugs (OR=4.97, CI=3.68-6.71), being referred to alcohol rehabilitation (OR=7.15, CI=4.84-10.58), and being convicted of driving under the influence (OR=4.84, CI=3.04-7.67).

CONCLUSIONS

Positive responses to a two-item alcohol screening tool were strongly associated with serious alcohol-related behaviors. This study highlights the need to improve screening and access to care for alcohol-related problems among service members returning from combat deployments.

Prevalence of mental health problems, treatment need, and barriers to care among primary care-seeking spouses of military service members involved in Iraq and Afghanistan deployments

Military spouses must contend with unique issues such as a mobile lifestyle, rules and regulations of military life, and frequent family separations including peacekeeping and combat deployments. These issues may have an adverse effect on the health of military spouses. This study examined the mental health status, rates of care utilization, source of care, as well as barriers and stigma of mental health care utilization among military spouses who were seeking care in military primary care clinics. The data show spouses have similar rates of mental health problems compared to soldiers. Spouses were more likely to seek care for their mental health problems and were less concerned with the stigma of mental health care than were soldiers. Services were most often received from primary care physicians, rather than specialty mental health professionals, which may relate to the lack of availability of mental health services for spouses on military installations.

Post-combat invincibility: violent combat experiences are associated with increased risk-taking propensity following deployment

Combat exposure is associated with increased rates of mental health problems such as post-traumatic stress disorder, depression, and anxiety when Soldiers return home. Another important health consequence of combat exposure involves the potential for increased risk-taking propensity and unsafe behavior among returning service members. Survey responses regarding 37 different combat experiences were collected from 1252 US Army Soldiers immediately upon return home from combat deployment during Operation Iraqi Freedom. A second survey that included the Evaluation of Risks Scale (EVAR) and questions about recent risky behavior was administered to these same Soldiers 3 months after the initial post-deployment survey. Combat experiences were reduced to seven factors using principal components analysis and used to predict post-deployment risk-propensity scores. Although effect sizes were small, specific combat experiences, including greater exposure to violent combat, killing another person, and contact with high levels of human trauma, were predictive of greater risk-taking propensity after homecoming. Greater exposure to these combat experiences was also predictive of actual risk-related behaviors in the preceding month, including more frequent and greater quantities of alcohol use and increased verbal and physical aggression toward others. Exposure to violent combat, human trauma, and having direct responsibility for taking the life of another person may alter an individual's perceived threshold of invincibility and slightly increase the propensity to engage in risky behavior upon returning home after wartime deployment. Findings highlight the importance of education and counseling for returning service members to mitigate the public health consequences of elevated risk-propensity associated with combat exposure.

Combat duty in Iraq and Afghanistan, mental health problems and barriers to care

BACKGROUND

The current combat operations in Iraq and Afghanistan have involved US military personnel in major ground combat and hazardous security duty. Studies are needed to systematically assess the mental health of members of the armed services who have participated in these operations and to inform policy with regard to the optimal delivery of mental health care to returning veterans.

METHODS

We studied members of 4 US combat infantry units (3 Army units and a Marine Corps unit) using an anonymous survey that was administered to the subjects either before their deployment to Iraq (n=2530) or 3 to 4 months after their return from combat duty in Iraq or Afghanistan (n=3671). The outcomes included major depression, generalized anxiety, and posttraumatic stress disorder (PTSD), which were evaluated on the basis of standardized, self-administered screening instruments.

RESULTS

Exposure to combat was significantly greater among those who were deployed to Iraq than among those deployed to Afghanistan. The percentage of study subjects whose responses met the screening criteria for major depression, generalized anxiety, or PTSD was significantly higher after duty in Iraq (15.6% to 17.1%) than after duty in Afghanistan (11.2%) or before deployment to Iraq (9.3%); the largest difference was in the rate of PTSD. Of those whose responses were positive for a mental disorder, only 23% to 40% sought mental health care. Those whose responses were positive for a mental disorder were twice as likely as those whose responses were negative to report concern about possible stigmatization and other barriers to seeking mental health care.

CONCLUSIONS

This study provides an initial look at the mental health of members of the Army and the Marine Corps who were involved in combat operations in Iraq and Afghanistan. Our findings indicate that among the study groups there was a significant risk of mental health problems and that the subjects reported important barriers to receiving mental health services, particularly the perception of stigma among those most in need of such care. The recent military operations in Iraq and Afghanistan, which have involved the first sustained ground combat undertaken by the United States since the war in Vietnam, raise important questions about the effect of the experience on the mental health of members of the military services who have been deployed there. Research conducted after other military conflicts has shown that deployment stressors and exposure to combat result in considerable risks of mental health problems, including posttraumatic stress disorder, major depression, substance abuse, impairment in social functioning and in the ability to work, and the increased use of healthcare services. One study that was conducted just before the military operations in Iraq and Afghanistan began found that at least 6% of all US military service members on active duty receive treatment for a mental disorder each year. Given the ongoing military operations in Iraq and Afghanistan, mental disorders are likely to remain an important healthcare concern among those serving there. Many gaps exist in the understanding of the full psychosocial effect of combat. The all-volunteer force deployed to Iraq and Afghanistan and the type of warfare conducted in these regions are very different from those involved in past wars, differences that highlight the need for studies of members of the armed services who are involved in the current operations. Most studies that have examined the effects of combat on mental health were conducted among veterans years after their military service had ended. A problem in the methods of such studies is the long recall period after exposure to combat. Very few studies have examined a broad range of mental health outcomes near to the time of subjects' deployment. Little of the existing research is useful in guiding policy with regard to how best to promote access to and the delivery of mental health care to members of the armed services. Although screening for mental health problems is now routine both before and after deployment and is encouraged in primary care settings, we are not aware of any studies that have assessed the use of mental health care, the perceived need for such care, and the perceived barriers to treatment among members of the military services before or after combat deployment. We studied the prevalence of mental health problems among members of the US armed services who were recruited from comparable combat units before or after their deployment to Iraq or Afghanistan. We identified the proportion of service members with mental health concerns who were not receiving care and the barriers they perceived to accessing and receiving such care.

Validating the primary care posttraumatic stress disorder screen and the posttraumatic stress disorder checklist with soldiers returning from combat

The purpose of the research was to assess the diagnostic efficiency of the Primary Care Posttraumatic Stress Disorder Screen (PC-PTSD) and the Posttraumatic Stress Disorder Checklist (PCL) as clinical screening tools for active duty soldiers recently returned from a combat deployment. A secondary goal was to examine the item-level characteristics of both the PC-PTSD and the PCL. A validation study conducted with a sample of 352 service members showed that both the PC-PTSD and PCL had good diagnostic efficiency. The overall diagnostic efficiency assessed by the area under the curve (AUC) was virtually the same for both the PC-PTSD and PCL. The most efficient cutoff values for the PC-PTSD were either 2 or 3 "yes" responses with the latter favoring specificity. For the PCL, the most efficient cutoff values were between 30 and 34, mirroring recommended PCL cutoff values from some studies in primary care settings. The examination of item characteristics suggested a 4-item PCL with an AUC virtually identical to that of the full PCL. Item analyses also identified that the most discriminate item in both scales pertained to symptoms of avoidance. Implications and limitations are discussed.

Mild traumatic brain injury in U.S. Soldiers returning from Iraq

BACKGROUND

An important medical concern of the Iraq war is the potential long-term effect of mild traumatic brain injury, or concussion, particularly from blast explosions. However, the epidemiology of combat-related mild traumatic brain injury is poorly understood.

METHODS

We surveyed 2525 U.S. Army infantry soldiers 3 to 4 months after their return from a year-long deployment to Iraq. Validated clinical instruments were used to compare soldiers reporting mild traumatic brain injury, defined as an injury with loss of consciousness or altered mental status (e.g., dazed or confused), with soldiers who reported other injuries.

RESULTS

Of 2525 soldiers, 124 (4.9%) reported injuries with loss of consciousness, 260 (10.3%) reported injuries with altered mental status, and 435 (17.2%) reported other injuries during deployment. Of those reporting loss of consciousness, 43.9% met criteria for post-traumatic stress disorder (PTSD), as compared with 27.3% of those reporting altered mental status, 16.2% with other injuries, and 9.1% with no injury. Soldiers with mild traumatic brain injury, primarily those who had loss of consciousness, were significantly more likely to report poor general health, missed workdays, medical visits, and a high number of somatic and postconcussive symptoms than were soldiers with other injuries. However, after adjustment for PTSD and depression, mild traumatic brain injury was no longer significantly associated with these physical health outcomes or symptoms, except for headache.

CONCLUSIONS

Mild traumatic brain injury (i.e., concussion) occurring among soldiers deployed in Iraq is strongly associated with PTSD and physical health problems 3 to 4 months after the soldiers return home. PTSD and depression are important mediators of the relationship between mild traumatic brain injury and physical health problems.

The impact of deactivation uncertainty, workload, and organizational constraints on reservists' psychological well-being and turnover intentions

This study assessed the impact of the activation of U.S. Army reservists after terrorists attacked the United States on September 11, 2001. A total of 263 soldiers completed a survey and participated in focus groups. The model's stressors were deactivation uncertainty, workload, and organizational constraints. The outcomes were well-being and turnover intentions. In general, most stressors did predict the proposed outcomes. That is, with high deactivation uncertainty, workload, or organizational constraints, reservists reported low psychological well-being and high turnover intentions. Commanders and policymakers can use our findings when addressing ways to improve reservists' psychological health and to decrease turnover intentions. Specifically, reservists need more predictability and the needed organizational conditions (i.e., proper workload levels and equipment) while activated and deployed to protect our country.

Childhood adversity and combat as predictors of depression and post-traumatic stress in deployed troops

BACKGROUND

Previous studies have shown a relationship between childhood adversity and health outcomes in adulthood. The military represents a segment of the young working population that faces unique hazards that may be worsened by previous adverse life experiences. To date, no comprehensive studies of childhood adversity have been conducted with military samples that have included combat troops before and after a combat deployment.

METHODS

Surveys were administered in 2003 to 4529 male soldiers who had not deployed to Iraq, and in 2004 to a separate group of 2392 male soldiers 3 months after returning from Iraq. The main predictor was adverse childhood experiences, an aggregated construct representing incremental exposure to six types of traumatic childhood experiences. This construct correlated with depression and post-traumatic stress disorder rates, as well as symptom scores. For the post-Iraq sample, analyses were conducted to assess whether individuals with childhood trauma were affected differently by exposure to combat.

RESULTS

The likelihood of screening positive for depression and post-traumatic stress disorder was significantly higher for individuals reporting exposure to two or more categories of childhood adversity. Core analyses showed that adverse childhood experiences were a significant predictor of mental health symptoms, beyond the expected contribution of combat.

CONCLUSIONS

This study confirms the high prevalence of adverse childhood experiences and the association of these experiences with key mental health outcomes. In addition, the results highlight the importance of considering pre-enlistment childhood traumatic experiences as well as the level of combat exposure in the treatment of military personnel returning from combat operations.

Non-linear function model of voice pitch dependency on physical and mental load

The present work describes that under increasing physical load the voice fundamental frequency (voice pitch) remains on a given level as long as the physical load is well tolerated by the subject, whereas heart rate and blood pressure continuously increase during increasing physical load. This voice pitch level was compared to voice pitch levels under mental load. Using a word recognition system, 11 well trained, young male subjects had to solve 2 moderate mental load tasks. Before, during and after each task, there were structured relaxation phases. The physical load protocol was a standard bicycle stress test. In each protocol phase the subjects had to count from 1 to 10 in order to provide a standardized speech sample. Heart rate and blood pressure were recorded in all phases. Voice frequency was at average 106 +/- 5.2 Hz in the relaxation phases ('rest level') and was increased under mental load (115.9 +/- 5.7 Hz, Pillais-P = 0.037). During physical stress testing, voice pitch remained unchanged ('tolerated load level') between 100 and 200 W (117.4 +/- 4.8 Hz) and increased shortly before physical exhaustion ('exhaustion level', 275-350 W, 142.9 +/- 5.6 Hz, Pillais-P = 0.007). In contrast, heart rate and blood pressure increased continuously with the physical load. Three voice pitch levels could be verified also individually for each subject. For the practical monitoring of emotional stress the individual anchor frequencies for these levels must be assessed. These data indicate that the relationship between both types of load and voice pitch is non-linear with multiple plateaus and transition functions between them.

Association of posttraumatic stress disorder with somatic symptoms, health care visits, and absenteeism among Iraq war veterans

OBJECTIVE

Studies of soldiers from prior wars conducted many years after combat have shown associations between combat-related posttraumatic stress disorder (PTSD) and physical health problems. The current Iraq war has posed a considerable PTSD risk, but the association with physical health has not been well studied.

METHOD

The authors studied 2,863 soldiers using standardized self-administered screening instruments 1 year after their return from combat duty in Iraq.

RESULTS

Among all participants, 16.6% met screening criteria for PTSD. PTSD was significantly associated with lower ratings of general health, more sick call visits, more missed workdays, more physical symptoms, and high somatic symptom severity. These results remained significant after control for being wounded or injured.

CONCLUSIONS

The high prevalence of PTSD and its strong association with physical health problems among Iraq war veterans have important implications for delivery of medical services. The medical burden of PTSD includes physical health problems; combat veterans with serious somatic concerns should be evaluated for PTSD.

Correlates and consequences of morale versus depression under stressful conditions

The role of morale as a positive psychological construct distinct from the construct of depression was examined using data from a longitudinal study of 1,685 U.S. soldiers on a peacekeeping mission to Kosovo. Structural equation modeling analyses revealed morale was best predicted by indices of engagement in meaningful work and confidence in unit functioning and leadership, whereas depression was best predicted by deployment stressors and negative events. Morale assessed during the deployment was related to perceiving benefits from deploying six months later, whereas depression was related to posttraumatic stress disorder and negative perceptions of deploying. The relationship between morale and benefits was a function of engagement in meaningful work. Discussion focuses on the importance of longitudinal research in specifying the antecedents of positive and negative outcomes of a stressful work environment.

Assessing risk propensity in American soldiers: preliminary reliability and validity of the Evaluation of Risks (EVAR) scale--English version

Risk-taking propensity is a critical component of judgment and decision-making in military operations. The Evaluation of Risks scale (EVAR) was recently developed to measure state and trait aspects of risk proneness. The scale, however, was psychometrically normed in French and no data are available for the English translation. We administered the English version of the EVAR to 165 U.S. soldiers to obtain reliability, validity, and normative data for English-speaking respondents. Confirmatory factor analysis suggested that the factor structure of the English EVAR differs from that obtained in the French studies. Instead, a three-factor solution, including recklessness/impulsivity, self-confidence, and need for control, emerged. Internal consistency was comparable to the French version. EVAR scores correlated with age, military rank, and years of service, and discriminated soldiers with histories of high-risk behavior. The data support the reliability and validity of the English version of the EVAR for evaluating risk propensity in U.S. soldiers.

The effects of prior combat experience on the expression of somatic and affective symptoms in deploying soldiers

OBJECTIVE

Deployment to a combat zone is undoubtedly an extremely stressful experience. It was hypothesized that, when faced with an impending wartime deployment, soldiers with prior combat experience would report minimal emotional problems accompanied by high rates of somatic complaints compared with combat-naive soldiers.

METHODS

Self-reports of posttraumatic stress disorder (PTSD) and affective and somatic complaints were collected from 2068 U.S. soldiers just prior to combat deployment during Operation Iraqi Freedom.

RESULTS

Although the percentage of soldiers scoring positive for PTSD was nearly identical for the experienced and inexperienced groups, scores on the Affective and Somatic scales differed as a function of prior combat history. Previous combat experience was associated with lower affective and greater somatic complaints relative to combat-naive soldiers.

CONCLUSIONS

Consistent with theories of stress reaction, repression, and somatic amplification, combat-experienced soldiers reported limited affective complaints but greater somatic complaints relative to soldiers without combat experience.

The impact of National Guard activation for homeland defense: employers' perspective

Data gathered from a study of reserve component (RC) soldiers who were activated during the spring of 2002, following the terrorist attacks of September 11, 2001, suggested that they were concerned about how the effects of their activation affected their civilian employment. Therefore, the purpose of this study was to obtain this information from the civilian employers of these RC soldiers. Most civilian employers who participated in this study (N = 28) were male (89%) and working in law enforcement (39%). Fifty-six percent of employers gave consent to be interviewed by telephone. Although supervisors reported difficulties in several areas of operation and aspects of the RC activation, they still supported the activation of their RC employees and their military mission. This study is a significant start to illuminating the important roles that both RC employees and their civilian employers play in homeland defense.

Psychological Screening Procedures for Deploying U.S. Forces

This study examined the validity of psychological measures used in screening for the U.S. Army with 885 soldiers before a 6-month peacekeeping rotation in Kosovo. Content validity and construct validity were assessed by evaluating the clinical domains, comparing clinician assessments of functioning, and assessing risk factors for screening positive. Construct validity and content validity were demonstrated. Risks, benefits, and future directions of the Army's psychological screening research program are discussed.

Combat duty in Iraq and Afghanistan, mental health problems, and barriers to care

BACKGROUND

The current combat operations in Iraq and Afghanistan have involved U.S. military personnel in major ground combat and hazardous security duty. Studies are needed to systematically assess the mental health of members of the armed services who have participated in these operations and to inform policy with regard to the optimal delivery of mental health care to returning veterans.

METHODS

We studied members of four U.S. combat infantry units (three Army units and one Marine Corps unit) using an anonymous survey that was administered to the subjects either before their deployment to Iraq (n=2530) or three to four months after their return from combat duty in Iraq or Afghanistan (n=3671). The outcomes included major depression, generalized anxiety, and post-traumatic stress disorder (PTSD), which were evaluated on the basis of standardized, self-administered screening instruments.

RESULTS

Exposure to combat was significantly greater among those who were deployed to Iraq than among those deployed to Afghanistan. The percentage of study subjects whose responses met the screening criteria for major depression, generalized anxiety, or PTSD was significantly higher after duty in Iraq (15.6 to 17.1 percent) than after duty in Afghanistan (11.2 percent) or before deployment to Iraq (9.3 percent); the largest difference was in the rate of PTSD. Of those whose responses were positive for a mental disorder, only 23 to 40 percent sought mental health care. Those whose responses were positive for a mental disorder were twice as likely as those whose responses were negative to report concern about possible stigmatization and other barriers to seeking mental health care.

CONCLUSIONS

This study provides an initial look at the mental health of members of the Army and the Marine Corps who were involved in combat operations in Iraq and Afghanistan. Our findings indicate that among the study groups there was a significant risk of mental health problems and that the subjects reported important barriers to receiving mental health services, particularly the perception of stigma among those most in need of such care.

Psychological screening program overview

This article reviews the literature on health surveillance conducted during military deployments, focusing on models for assessing the impact of operational deployments on peacekeepers. A discussion of the stressors and potential mental health consequences of peacekeeping operations follows with relevant examples of findings from U.S. and international military forces. Psychological screening in different peacekeeping operations conducted in U.S. Army-Europe is reviewed. The review begins with the redeployment screening of military personnel deployed to Bosnia mandated under the Joint Medical Surveillance Program, and continues through the present screening of units deployed to Kosovo. The detailed description of the screening program includes a discussion of procedures and measures and demonstrates the evolution of the program. A summary of key findings from the screening program and a discussion of future research directions are provided.

Enteral feeding in stable chronic obstructive pulmonary disease patients

OBJECTIVE

The study aimed to compare the effectiveness of a defined formula diet with a blenderized diet on nutritional and respiratory function parameters and to determine the bacteriological load of the two formulations.

METHODOLOGY

Seventeen patients, aged 50-75 years, admitted to the University of the Philippines-Philippine General Hospital for chronic bronchitis and/or emphysema, were studied. They were divided into two groups according to dietary regimens. Each group of patients received either the standardized commercial formula or the blenderized formula for 2 weeks. Evaluation of dietary intake, anthropometric measurements, laboratory examinations and lung function were assessed. Subjective evaluation (patient's and physician's assessment) was also sought. Microbiological examinations were performed on the prepared enteral formulas.

RESULTS

There was a slight increase in weight and in pulmonary function in both groups but these results did not differ significantly. Possible formula contamination was confirmed. Furthermore, in the overall assessment, the physician and patients rated both formulas as comparable.

Radioprotective and locomotor responses of mice treated with nimodipine alone and in combination with WR-151327

The effect of combining a radiation-protective phosphorothioate with another agent was investigated in an attempt to increase radioprotection and reduce toxicity. The calcium channel blocker nimodipine (NIMO) was administered alone (1 or 10 mg kg-1) or in combination with 200 mg kg-1 of the phosphorothioate radioprotector WR-151327 (WR) (S-3-(3-methylaminopropylamino)propylphosphorothioic acid). Radioprotection as measured (30-day survival) of mice treated i.p. 30 min before (60)Co irradiation at a dose rate of 1 Gy min-1 was evaluated in CD2F1 male mice. The effects of nimodipine and WR-151327 on locomotor activity were investigated also in a separate group of non-irradiated mice. The LD(50/30) for the Emulphor vehicle control group was 8.56. For nimodipine alone (1 or 10 mg kg-1) the LD(50/30)was 8.39 and 10.21 Gy, respectively, yielding dose modification factors (DMFs) of 0.98 and 1.19, respectively. When WR-151327 was given alone, the <LD(50/30) was 12.48 Gy (DMF = 1.46; P < 0.05 from vehicle). WR-151327 combined with 1 or 10 mg kg-1 nimodipine resulted in an LD(50/30) of 12.73 Gy (DMF 1.49, P < 0.05 from vehicle), and when WR-151327 was combined with 10 mg kg-1 nimodipine the LD(50/30) was 14.29 Gy (DMF = 1.67, P < 0.001 from WR-151327). For either dose of nimodipine, locomotor activity did not differ from vehicle. WR-151327 and WR-151327 + 1 mg kg-1 nimodipine resulted in locomotor decrements for up to 4 h post-administration (P < 0.05 from vehicle), and WR-151327 + 10 mg kg-1 nimodipine for up to 6 h (P < 0.05 from WR-151327). Therefore, although there was an additive radioprotective effect when the higher dose of nimodipine was combined with WR-151327, the locomotor decrement was also enhanced. These results demonstrate that a combination of nimodipine and a phosphorothioate such as WR-151327 may be useful as a clinical setting where behavioral and physiological side-effects can be monitored. Published in 2001 by John Wiley & Sons, Ltd.

The Oklahoma Postmenopausal Women's Health Study: recruitment and characteristics of American Indian, Asian, Black, Hispanic, and Caucasian women

Since 1994, the National Institutes of Health has required the inclusion of women and minorities in all of its sponsored clinical research. This study describes a workable recruitment strategy that embraces the National Institutes of Health requirement. We describe the recruitment pattern of the Oklahoma Postmenopausal Women's Study conducted in the general community of Oklahoma City and in surrounding areas that are both urban and rural. For the period 1994 through 1997, 491 postmenopausal women from all racial/ethnic groups in the community have participated in this study. Over 4 years of recruitment, the percentage of minority women in the study population has risen annually from 31% in 1994 to 81% in 1997. The overall percentage of minority women in the study population is currently 63.3%: American Indian, 21.8%; Asian, 3.7%; Black, 14.9%; Hispanic, 9.4%; White/American Indian Blend, 13.6%; and White, 36.7%. The recruitment approach described may be implemented in a variety of research settings. Specific recruitment approaches are described, as well as the distribution of sociodemographic and health behaviors across and within ethnic/racial groups.

Primacy and recency effects in rhesus monkeys (Macaca mulatta) using a serial probe recognition task. III. A developmental analysis

In children, the recency effect emerges prior to the primacy effect. To determine whether this dissociation is also seen in nonhuman primates, we evaluated the development of the primacy and recency effect in 3 young adult (35 months) and 4 adolescent (21 months) male rhesus monkeys (Macaca mulatta) using a six-item serial probe recognition (SPR) task. As predicted, the young adult monkeys displayed both effects, while the adolescent monkeys only displayed the recency effect. Not until after 26 months of training on the SPR task did the adolescent monkeys exhibit both the primacy and recency effect. Interference and strategy differences are discussed in terms of the results along with an interpretation of Rudy's (1992) configural association theory of cognitive development. Additional possible explanations for this developmental dissociation include the delayed maturation of the neocortical, hippocampal, and/or cholinergic systems, the latter two having been shown to be important in the expression of the primacy but not the recency effect.

Primacy and recency effects in rhesus monkeys (Macaca mulatta) using a serial probe recognition task: II. Effects of atropine sulfate

Nonhuman primates display both a primacy and a recency effect when trained on a 6-item serial probe recognition task. The author has previously shown that in the rhesus monkey, diazepam (3.2 mg/kg im) interferes with the memory processes that mediate the recency effect without affecting those memory processes involved in the primacy effect (C. A. Castro, 1995). This study assessed the effects of atropine sulfate (0.2, 0.3, and 0.4 mg/kg im) on the primacy and recency effects in these same monkeys. Opposite the effects of diazepam, atropine disrupted the primacy component of the serial position curve and had no measurable effect on the recency component. In addition, the 2 highest doses of atropine disrupted accuracy on the nonmatching probe trials, whereas all 3 doses of atropine resulted in increased response latencies. These reports indicate that the primacy and recency effects in the nonhuman primate can be pharmacologically dissociated.

Primacy and recency effects in rhesus monkeys (Macaca mulatta) using a serial probe recognition task: II. Effects of atropine sulfate

Nonhuman primates display both a primacy and a recency effect when trained on a 6-item serial probe recognition task. The author has previously shown that in the rhesus monkey, diazepam (3.2 mg/kg im) interferes with the memory processes that mediate the recency effect without affecting those memory processes involved in the primacy effect (C. A. Castro, 1995). This study assessed the effects of atropine sulfate (0.2, 0.3, and 0.4 mg/kg im) on the primacy and recency effects in these same monkeys. Opposite the effects of diazepam, atropine disrupted the primacy component of the serial position curve and had no measurable effect on the recency component. In addition, the 2 highest doses of atropine disrupted accuracy on the nonmatching probe trials, whereas all 3 doses of atropine resulted in increased response latencies. These reports indicate that the primacy and recency effects in the nonhuman primate can be pharmacologically dissociated.

Primacy and recency effects in rhesus monkeys (Macaca mulatta) using a serial probe recognition task. I. Effects of diazepam

In this study, we evaluated the effects of diazepam (0.2, 0.8, 1.6 and 3.2 mg/kg; IM) on the primacy and recency memory effects in four rhesus monkeys trained on a six-item serial probe recognition (SPR) task. Only the highest dose of diazepam (3.2 mg/kg) consistently affected the shape of the monkeys' serial position curves. Accuracy on the probe trials was disrupted for list items which occurred in the middle portion and recency memory component of the serial position curve, without affecting the primacy component. Diazepam, however, also produced several nonspecific effects on SPR performance. Both the 1.6 and 3.2 mg/kg diazepam doses disrupted accuracy on the non-matching probe trials, and the 3.2 mg/kg dose caused an increase in response latencies which were unrelated to any one component of the serial position curve. This is the first demonstration in nonhuman primates showing that the primacy and recency memory effects can be differentiated on the basis of diazepam dose.

Behavioral effects of vehicles: DMSO, ethanol, Tween-20, Tween-80, and emulphor-620

Experimental drugs and compounds that do not easily dissolve in water or saline are frequently combined with vehicles like solvents, detergents, or vegetable oils. Yet very little has been reported on the behavioral effects of vehicles. In this study, we assessed the effects of a vegetable oil (emulphor-620), two detergents (Tween-20 and Tween-80), and two solvents [dimethyl sulphoxide (DMSO) and ethanol] on the locomotor activity in CD2F1 male mice. Locomotor activity was monitored for 12 h after vehicle administration (IP). The concentrations for each vehicle were expressed as percent of vehicle in saline (v/v). Emulphor-620 did not affect locomotor activity at any concentration tested (2%, 4%, 8%, 16%, and 32%). Tween-20 significantly decreased locomotor activity at a concentration of 16% and Tween-80 at 32%. DMSO significantly decreased locomotor activity at concentrations of 32% and 64%. In contrast, ethanol produced a biphasic behavioral response: increased activity at a concentration of 16% and decreased activity at a concentration of 32%. These results will facilitate the selection and concentration of vehicles to be used in combination with experimental drugs or test agents.

Behavioral decrements persist in rhesus monkeys trained on a serial probe recognition task despite protection against soman lethality by butyrylcholinesterase

Recently, it has been demonstrated that an exogenously administered enzyme such as butyrylcholinesterase (BuChE) can prevent death in rhesus monkeys exposed to multiple-lethal doses of the acetylcholinesterase inhibitor soman when the enzyme is given prior to soman exposure (3). We report that despite BuChE protecting against soman-induced lethality, behavioral effects are seen in these monkeys which last for at least 6 days as measured by performance on a serial probe recognition (SPR) task. Analyses of the serial position curves showed that performance was lower on the probe trials when the probe items were from the middle of the list than when the probe items were from the beginning or end of the list which were unaffected. BuChE given alone also produced behavioral effects, causing all animals not to respond on the probe trials until 8 h following BuChE administration. Taken together, these findings suggest that the BuChE is not completely binding all of the soman and that a concentration of soman which is capable of causing behavioral effects may be entering the CNS.

Impaired short-term memory resulting from postnatal undernutrition is attenuated by physostigmine

Early-life undernutrition impairs the short-term memory capacity of adult rats (90 days of age) trained on a conditional-spatial discrimination task (Castro, Tracy, & Rudy, Behavioral Brain Research, 32, 255-264, 1989). While well-nourished control animals perform above 90% correct when the interval separating the forced run and choice run is 180 s, the performance of the undernourished animals falls to chance (50%) when the delay interval is increased to 90 s. We now report that this performance decrement can be attenuated by the administration of the anticholinesterase, physostigmine. However, the effects of physostigmine were dose dependent. While 0.02 mg/kg of physostigmine improved the performance of the undernourished animals so that they performed significantly above chance at the 180-s delay interval, neither 0.2 nor 0.002 mg/kg of physostigmine improved performance. We concluded that this effect was centrally mediated since scopolamine hydrobromide (1.0 mg/kg) which blocks both central and peripheral cholinergic receptors blocked physostigmine's performance-improving effect, while methyl-scopolamine (1.0 mg/kg) which blocks only peripheral receptors did not. These are the first results which suggest that the short-term memory impairments produced by early-life undernutrition can be attenuated by enhancing central cholinergic functioning.

Cholinesterases as scavengers for organophosphorus compounds: protection of primate performance against soman toxicity

The present treatment for poisoning by organophosphates consists of multiple drugs such as carbamates, antimuscarinics, and reactivators in pre- and post-exposure modalities. Recently an anticonvulsant, diazapam, has been included as a post-exposure drug to reduce convulsions and increase survival. Most regimens are effective in preventing lethality from organophosphate exposure but do not prevent toxic effects and incapacitation observed in animals and likely to occur in humans. Use of enzymes such as cholinesterases as pretreatment drugs for sequestration of highly toxic organophosphate anticholinesterases and alleviation of side effects and performance decrements was successful in animals, including non-human primates. Pretreatment of rhesus monkeys with fetal bovine serum acetylcholinesterase protected them against lethal effects of soman (up to 5 LD50) and prevented signs of OP toxicity. Monkeys pretreated with fetal bovine serum acetylcholinesterase were devoid of behavioral incapacitation after soman exposure, as measured by serial probe recognition or primate equilibrium platform performance tasks. Use of acetylcholinesterase as a single pretreatment drug provided greater protection against both lethal and behavioral effects of potent organophosphates than current multicomponent drug treatments that prevent neither signs of toxicity nor behavioral deficits. Although use of cholinesterases as single pretreatment drugs provided complete protection, its use for humans may be limited, since large quantities will be required, due to the approximately 1:1 stoichiometry between organophosphate and enzyme. Bisquaternary oximes, particularly HI-6, have been shown to reactivate organophosphate-inhibited acetylcholinesterase at a rapid rate. We explored the possibility that enzyme could be continually reactivated in animals pretreated with fetal bovine serum acetylcholinesterase, followed by an appropriate dose of reactivator, and challenged with repeated doses of sarin. In in vitro experiments, stoichiometry greater than 1:400 for enzyme:sarin was achieved; in vivo stoichiometry in mice was 1:65. Pretreatment of mice with fetal bovine serum acetylcholinesterase and HI-6 amplified the effectiveness of exogenous enzyme as a scavenger for organophosphate.

Primacy and recency effects in nonhuman primates

The reports of primacy and recency memory effects in nonhuman primates have been criticized because they have all used an initiating response. That is, the presentation of the to-be-remembered list of items was always contingent on a response being initiated by the nonhuman primate. It has been argued that this initiating response improves performance for early items in the list, resulting in the occurrence of the primacy effect, independent of any memory processing mechanism. This criticism was addressed in the present study by not using an initiating response prior to the presentation of the list. Nevertheless, both a primacy and a recency effect were observed in all 6 rhesus monkeys evaluated using a serial probe recognition task. Thus, the results are similar to those for humans, in that both primacy and recency effects can be obtained in nonhuman primates. A brief literature review is included, and it is proposed that the primacy and recency effects observed in humans, nonhuman primates, and infraprimates can be explained within the context of the configural-association theory.

Protection of rhesus monkeys against soman and prevention of performance decrement by pretreatment with acetylcholinesterase

The ability of acetylcholinesterase from fetal bovine serum (FBS AChE) to protect against soman, a highly toxic organophosphorus (OP) compound, was tested in rhesus monkeys. Intravenous administration of FBS AChE produced a minimal behavioral effect on the serial probe recognition task, a sensitive test of cognitive function and short-term memory. Pharmacokinetic studies of injected FBS AChE indicated a plasma half-life of 40 hr for FBS AChE in monkeys. Both in vitro and in vivo titration of FBS AChE with soman produced a 1:1 stoichiometry between organophosphate-inhibited FBS AChE and the cumulative dose of the toxic stereoisomers of soman. Administration of FBS AChE protected monkeys against the lethal effects of up to 2.7 LD50 of soman and prevented any signs of organophosphate intoxication, e.g., excessive secretions, respiratory depression, muscle fasciculations, or convulsions. In addition, monkeys pretreated with FBS AChE were devoid of any behavioral incapacitation after soman challenge, as measured by the serial probe recognition task. Compared to the current multicomponent drug treatment against soman, which does not prevent the signs or the behavioral deficits resulting from OP intoxication, use of FBS AChE as a single pretreatment drug provides significantly effective protection against both the lethal and the behavioral effects of soman.

Primacy and recency effects in nonhuman primates

The reports of primacy and recency memory effects in nonhuman primates have been criticized because they have all used an initiating response. That is, the presentation of the to-be-remembered list of items was always contingent on a response being initiated by the nonhuman primate. It has been argued that this initiating response improves performance for early items in the list, resulting in the occurrence of the primacy effect, independent of any memory processing mechanism. This criticism was addressed in the present study by not using an initiating response prior to the presentation of the list. Nevertheless, both a primacy and a recency effect were observed in all 6 rhesus monkeys evaluated using a serial probe recognition task. Thus, the results are similar to those for humans, in that both primacy and recency effects can be obtained in nonhuman primates. A brief literature review is included, and it is proposed that the primacy and recency effects observed in humans, nonhuman primates, and infraprimates can be explained within the context of the configural-association theory.

Behavioral efficacy of diazepam against nerve agent exposure in rhesus monkeys

The possibility that nerve agents will be used on the battlefield is real. The traditional therapy against nerve agent exposure consists of pyridostigmine pretreatment and atropine-pralidoxime chloride therapy administered after nerve agent exposure. This therapy regimen is extremely effective in preventing mortality in laboratory animals exposed to multilethal concentrations of nerve agent, yet these animals often display convulsions, brain damage, and behavioral incapacitation. We report here that the addition of diazepam to the traditional therapy for nerve agent (soman) exposure not only decreases the incidence of convulsions, but also attenuates the cognitive impairments of rhesus monkeys trained on a Serial Probe Recognition (SPR) task. Monkeys which received diazepam treatment required only 6 days before their performance on the SPR task returned to presoman exposure levels, compared to nondiazepam-treated monkeys which required 15 days. Moreover, only 1 out of the 5 monkeys which received diazepam treatment suffered tonic-clonic convulsions; in contrast all 5 monkeys which did not receive diazepam treatment experienced severe convulsive episodes. These results suggest that diazepam would be an excellent adjunct to traditional nerve agent therapy to facilitate behavioral recovery from nerve agent intoxication that might be encountered by US military personnel on the battlefield or accidental organophosphate poisoning encountered in industrial or agricultural accidents.

Protection by butyrylcholinesterase against organophosphorus poisoning in nonhuman primates

Butyrylcholinesterase (BuChE) was examined as an in vivo exogenous scavenger for highly toxic organophosphorus (OP) poisons. Protection studies with equine BuChE were carried out in rhesus monkeys trained to perform a Serial Probe Recognition task. The pharmacokinetics of equine BuChE administered i.v. in rhesus monkeys revealed an elimination T1/2 of approximately 620 hr. Animals given 503 nmol of BuChE i.v. and then challenged with 220 to 260 nmol of soman (two LD50; a lethal dose in untreated animals) all survived with no clinical signs of OP poisoning. Serial Probe Recognition performance was depressed after enzyme administration and at 1 hr postsoman. However, all monkeys performed the task at base-line levels at 8 hr after soman and throughout the remainder of the experimental period. Two different monkeys each were given two doses of sarin, 183 nmol/dose (one LD50) after 460 nmol of BuChE. No signs were observed. A third group of monkeys given 253 or 340 nmol (three and four LD50, respectively) of soman after 460 nmol of BuChE required 1 mg/kg of atropine i.v. 10 min postsoman, but recovered completely within 24 hr. Our results indicate that BuChE has the required properties to function as a biological scavenger to protect against the pharmacological and behavioral toxicity of OP poisons.

Competition between Li+ and Mg2+ for ATP and ADP in aqueous solution: a multinuclear NMR study

We used 7Li NMR spin-lattice relaxation times and 31P NMR chemical shifts to study the binding of Li+ and Mg2+ to the phosphate moieties of ATP and ADP. To examine the binding of Li+ and Mg2+ to the base and ribose moieties, we used 1H and 13C NMR chemical shifts. The 7Li NMR relaxation times of Li+/Mg2+ mixtures of ATP or ADP increased with increasing concentrations of Mg2+, suggesting competition between the two ions for adenine nucleotides. No significant binding of Li+ and Mg2+ to the base and ribose moieties occurred. At the pH and ionic strength used, 2:1 and 1:1 species of the Li(+)-ATP and Li+-ADP complexes were present, with the 2:1 species predominating. In contrast, 1:1 species predominated for the Mg(2+)-ADP and Mg(2+)-ATP complexes. We calculated the Li(+)-nucleotide binding constants in the presence and absence of Mg2+ and found them to be somewhat greater in the presence of Mg2+. Although competition between Li+ and Mg2+ for ATP and ADP phosphate binding sites in solution is consistent with the 31P chemical shift data, the possibility that the Li+ and Mg2+ form mixed complexes with the phosphate groups of ATP or ADP cannot be ruled out.

Undernutrition during the brain growth period of the rat significantly delays the development of processes mediating Pavlovian trace conditioning

Pavlovian trace conditioning procedures allow one to assess the ability of animals to associate events that are temporally separated because the conditioned stimulus terminates prior to the occurrence of the unconditioned stimulus. We report that undernutrition during Postnatal Days 2-18 significantly delays the development of trace conditioning to a visual stimulus. Previously undernourished 20-day-old rats conditioned when no temporal interval separated the termination of the CS and US onset (0-s trace interval). However, it was not until the undernourished pups were 30 days old that they conditioned when the trace interval was 10 or 30 s. In contrast, control pups only 20 days old were able to condition when a 10-s trace interval separated the CS and US events, and 25-day-old control pups conditioned when the interval was either 10 or 30 s. These results suggest that undernutrition delays the development of processes that enable the rat to sustain a representation of a visual CS during the trace interval.

The cholinergic agent physostigmine enhances short-term-memory-based performance in the developing rat

There are age-related differences in the rat's short-term memory processes. Rats 24-25 days old are 90% correct when the delay interval separating the forced run and choice run of a trial is either 10 or 30 s, but they perform at chance when the delay interval is 60 s. In contrast, the choice performance of 30-day-old rats remains constant across all delay intervals. It is reported that the cholinergic agent physostigmine dramatically improved the short-term-memory-based performance of rats 24-25 days old such that they displayed no loss in choice accuracy even when the delay interval was 60 s. No such enhanced performance was seen in rats treated with neostigmine, a peripherally acting anticholinesterase. The results support the hypothesis that postnatal maturational differences in central cholinergic systems may contribute to age-related differences in short-term memory.

Recovery of spatial learning deficits after decay of electrically induced synaptic enhancement in the hippocampus

A widespread interest in a long-lasting form of synaptic enhancement in hippocampal circuits has arisen largely because it might reflect the activation of physiological mechanisms that underlie rapid associative learning. As its induction normally requires the 'Hebbian' association of activity on a number of input fibres, we refer to the process as long-term enhancement (LTE) rather than long-term potentiation (LTP), to emphasize its distinction from the ubiquitous, non-associative 'potentiation' phenomena that occur at most synapses, including those exhibiting LTE. Among other evidence that LTE might actually have a role in associative memory is the demonstration that repeated high-frequency stimulation, which saturated the inducible LTE, caused a severe deficit in spatial learning, although it had no effect on well established spatial memory. These results were consistent with a widespread view that information need only temporarily be stored in the hippocampal formation in order for long-term memories to be established in neocortical circuits. In this context, it is important to understand whether the possible underlying synaptic changes are of a permanent character, or are relatively transient. A second question is whether the actual cause of the observed learning deficit is the distruption of the synaptic weight distribution, and/or the limitation of further synaptic change, which presumably results from experimental saturation of the LTE mechanism. Alternatively, the deficit could be a consequence of some unobserved secondary effect of the high-frequency electrical stimulation. Here we demonstrate that learning capacity recovers in about the same time that it takes LTE to decay, which strongly favours the first possibility and supports the idea that LTE-like processes actually underlie associative memory.