Psychometric analysis of the PTSD Checklist-5 (PCL-5) among treatment-seeking military service members

The Posttraumatic Stress Disorder Checklist (PCL-5; Weathers et al., 2013) was recently revised to reflect the changed diagnostic criteria for posttraumatic stress disorder (PTSD) in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; American Psychiatric Association, 2013). We investigated the psychometric properties of PCL-5 scores in a large cohort (N = 912) of military service members seeking PTSD treatment while stationed in garrison. We examined the internal consistency, convergent and discriminant validity, and DSM-5 factor structure of PCL-5 scores, their sensitivity to clinical change relative to PTSD Symptom Scale-Interview (PSS-I; Foa, Riggs, Dancu, & Rothbaum, 1993) scores, and their diagnostic utility for predicting a PTSD diagnosis based on various measures and scoring rules. PCL-5 scores exhibited high internal consistency. There was strong agreement between the order of hypothesized and observed correlations among PCL-5 and criterion measure scores. The best-fitting structural model was a 7-factor hybrid model (Armour et al., 2015), which demonstrated closer fit than all other models evaluated, including the DSM-5 model. The PCL-5's sensitivity to clinical change, pre- to posttreatment, was comparable with that of the PSS-I. Optimally efficient cut scores for predicting PTSD diagnosis were consistent with prior research with service members (Hoge, Riviere, Wilk, Herrell, & Weathers, 2014). The results indicate that the PCL-5 is a psychometrically sound measure of DSM-5 PTSD symptoms that is useful for identifying provisional PTSD diagnostic status, quantifying PTSD symptom severity, and detecting clinical change over time in PTSD symptoms among service members seeking treatment. (PsycINFO Database Record

Behavior therapy for children with Tourette disorder: a randomized controlled trial

CONTEXT

Tourette disorder is a chronic and typically impairing childhood-onset neurologic condition. Antipsychotic medications, the first-line treatments for moderate to severe tics, are often associated with adverse effects. Behavioral interventions, although promising, have not been evaluated in large-scale controlled trials.

OBJECTIVE

To determine the efficacy of a comprehensive behavioral intervention for reducing tic severity in children and adolescents.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, observer-blind, controlled trial of 126 children recruited from December 2004 through May 2007 and aged 9 through 17 years, with impairing Tourette or chronic tic disorder as a primary diagnosis, randomly assigned to 8 sessions during 10 weeks of behavior therapy (n = 61) or a control treatment consisting of supportive therapy and education (n = 65). Responders received 3 monthly booster treatment sessions and were reassessed at 3 and 6 months following treatment.

INTERVENTION

Comprehensive behavioral intervention.

MAIN OUTCOME MEASURES

Yale Global Tic Severity Scale (range 0-50, score >15 indicating clinically significant tics) and Clinical Global Impressions-Improvement Scale (range 1 [very much improved] to 8 [very much worse]).

RESULTS

Behavioral intervention led to a significantly greater decrease on the Yale Global Tic Severity Scale (24.7 [95% confidence interval {CI}, 23.1-26.3] to 17.1 [95% CI, 15.1-19.1]) from baseline to end point compared with the control treatment (24.6 [95% CI, 23.2-26.0] to 21.1 [95% CI, 19.2-23.0]) (P < .001; difference between groups, 4.1; 95% CI, 2.0-6.2) (effect size = 0.68). Significantly more children receiving behavioral intervention compared with those in the control group were rated as being very much improved or much improved on the Clinical Global Impressions-Improvement scale (52.5% vs 18.5%, respectively; P < .001; number needed to treat = 3). Attrition was low (12/126, or 9.5%); tic worsening was reported by 4% of children (5/126). Treatment gains were durable, with 87% of available responders to behavior therapy exhibiting continued benefit 6 months following treatment.

CONCLUSION

A comprehensive behavioral intervention, compared with supportive therapy and education, resulted in greater improvement in symptom severity among children with Tourette and chronic tic disorder.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00218777.

International meta-analysis of PTSD genome-wide association studies identifies sex- and ancestry-specific genetic risk loci

The risk of posttraumatic stress disorder (PTSD) following trauma is heritable, but robust common variants have yet to be identified. In a multi-ethnic cohort including over 30,000 PTSD cases and 170,000 controls we conduct a genome-wide association study of PTSD. We demonstrate SNP-based heritability estimates of 5-20%, varying by sex. Three genome-wide significant loci are identified, 2 in European and 1 in African-ancestry analyses. Analyses stratified by sex implicate 3 additional loci in men. Along with other novel genes and non-coding RNAs, a Parkinson's disease gene involved in dopamine regulation, PARK2, is associated with PTSD. Finally, we demonstrate that polygenic risk for PTSD is significantly predictive of re-experiencing symptoms in the Million Veteran Program dataset, although specific loci did not replicate. These results demonstrate the role of genetic variation in the biology of risk for PTSD and highlight the necessity of conducting sex-stratified analyses and expanding GWAS beyond European ancestry populations.

T-brain-1: a homolog of Brachyury whose expression defines molecularly distinct domains within the cerebral cortex

The mechanisms that regulate regional specification and evolution of the cerebral cortex are obscure. To this end, we have identified and characterized a novel murine and human gene encoding a putative transcription factor related to the Brachyury (T) gene that is expressed only in postmitotic cells. T-brain-1 (Tbr-1) mRNA is largely restricted to the cerebral cortex, where during embryogenesis it distinguishes domains that we propose may give rise to paleocortex, limbic cortex, and neocortex. Tbr-1 and Id-2 expression in the neocortex have discontinuities that define molecularly distinct neocortical areas. Tbr-1 expression is analyzed in the context of the prosomeric model. Topological maps are proposed for the organization of the dorsal telencephalon.

Factors affecting auditory performance of postlinguistically deaf adults using cochlear implants

A model of auditory performance and a model of ganglion cell survival in postlinguistically deafened adult cochlear implant users are suggested to describe the effects of aetiology, duration of deafness, age at implantation, age at onset of deafness, and duration of implant use. The models were compared with published data and a composite data set including 808 implant users. Qualitative agreement with the model of auditory performance was found. Duration of deafness had a strong negative effect on performance. Age at implantation had a slight negative effect on performance, increasing after age 60 years. Age at onset of deafness had little effect on performance up to age 60. Duration of implant use had a positive effect on performance. Aetiology had a relatively weak effect on performance.

Genetic analysis of monoclonal antibody and HIV binding sites on the human lymphocyte antigen CD4

Saturation mutagenesis and a complement fixation selection have yielded CD4 point mutants with impaired antibody and human immunodeficiency virus binding. The patterns of amino acid substitution, in conjunction with previous antibody cross-blocking data, affirm the similar tertiary structures of the CD4 amino-terminal domain and immunoglobulin variable regions. Single residue substitutions affecting virus binding and syncytium formation are observed over an eight residue segment located in a portion of the molecule homologous to the second hypervariable region of an antibody combining site.

Myelination in the absence of myelin-associated glycoprotein

The hypothesis that myelin-associated glycoprotein (MAG) initiates myelin formation is based in part on observations that MAG has an adhesive role in interactions between oligodendrocytes and neurons. Furthermore, the over- or underexpression of MAG in transfected Schwann cells in vitro leads to accelerated myelination or hypomyelination, respectively. Here we test this idea by creating a null mutation in the mag locus and deriving mice that are totally deficient in MAG expression at the RNA and protein level. In adult mutant animals the degree of myelination and its compaction are normal, whereas the organization of the periaxonal region is partially impaired. Mutant animals show a subtle intention tremor. Our findings do not support the widely held view that MAG is critical for myelin formation but rather indicate that MAG is necessary for maintenance of the cytoplasmic collar and periaxonal space of myelinated fibres.

Dynamic markers of altered gait rhythm in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a disorder marked by loss of motoneurons. We hypothesized that subjects with ALS would have an altered gait rhythm, with an increase in both the magnitude of the stride-to-stride fluctuations and perturbations in the fluctuation dynamics. To test for this locomotor instability, we quantitatively compared the gait rhythm of subjects with ALS with that of normal controls and with that of subjects with Parkinson's disease (PD) and Huntington's disease (HD), pathologies of the basal ganglia. Subjects walked for 5 min at their usual pace wearing an ankle-worn recorder that enabled determination of the duration of each stride and of stride-to-stride fluctuations. We found that the gait of patients with ALS is less steady and more temporally disorganized compared with that of healthy controls. In addition, advanced ALS, HD, and PD were associated with certain common, as well as apparently distinct, features of altered stride dynamics. Thus stride-to-stride control of gait rhythm is apparently compromised with ALS. Moreover, a matrix of markers based on gait dynamics may be useful in characterizing certain pathologies of motor control and, possibly, in quantitatively monitoring disease progression and evaluating therapeutic interventions.

Mutagenesis by chemical agents in V79 chinese hamster cells: a review and analysis of the literature. A report of the Gene-Tox Program

The report reviews and evaluates the current literature (about 125 primary publications) on chemically induced specific locus mutations in the V79 Chinese hamster lung cell line. The V79 cell is convenient to use for mutagenesis studies since it has a rapid growth rate, high plating efficiency, and a stable karyotype. Mutation can be easily measured at either the hypoxanthine-guanine phosphoribosyl transferase or the Na+/K+ ATPase locus, both of which have been well characterized. Other less-studied markers are also described. We discuss the protocols for quantitative mutation studies including measurements of cytotoxicity, mutant expression times, mutant selection agents, cell densities during selection, and the stability and verification of mutant phenotypes. Mutations in the V79 cells by chemicals that require activation can be tested after their metabolism by cell homogenates or by intact cells, and the results with each type of activation are compared. For purposes of analysis, we classified a compound as mutagenic if it induced a mutation frequency that is at least 3 times higher than the spontaneous mutant frequency reported for that specific experiment. By this criterion two-thirds of the chemicals analyzed were mutagenic--; 11% with and 55% without metabolic activation. Of the 191 chemicals examined; 119 were polycyclic aromatic hydrocarbons; 25 were nitro or nitroso compounds, 9 were alkyl halides; 7 were purine or pyrimidine derivatives and the remaining 31 were from other chemical classes. We also defined mutagenic potency as the concentration of a compound that increases the mutant frequency by 10 times the spontaneous frequency. Mutagenic potencies of the compounds examined varied over a range of 5 X 10(6). We have also found large interlaboratory variations in the mutagenic potencies. Such variation in potency could be reduced by normalizing the results to a standard mutagen such as N-methyl-N'-nitro-N-nitrosoguanidine. The role of the V79 assay in mutagenicity and carcinogenicity testing is discussed and recommendations are suggested for future investigation.

Neurofilament-deficient axons and perikaryal aggregates in viable transgenic mice expressing a neurofilament-beta-galactosidase fusion protein

Interactions between neurofilament side arms may modulate axon caliber. To investigate this hypothesis, we derived transgenic mice expressing a fusion protein in which the carboxyl terminus of the high molecular weight neurofilament protein (NFH) was replaced by beta-galactosidase. The transgene, regulated by NFH sequences, was expressed in projection neurons. However, the fusion protein remained in perikarya precipitating large filamentous aggregates. Axons were not invested with neurofilaments and developed only small calibers. Perikaryal aggregates, with similar structural features, are associated with neurodegenerative diseases, but these mice showed few ill effects and their neurons rarely degenerated. We conclude that an organized neurofilament cytoskeleton is required by axons to achieve large calibers but is not essential for neuronal function or extended survival.

Effect of Prolonged Exposure Therapy Delivered Over 2 Weeks vs 8 Weeks vs Present-Centered Therapy on PTSD Symptom Severity in Military Personnel: A Randomized Clinical Trial

IMPORTANCE

Effective and efficient treatment is needed for posttraumatic stress disorder (PTSD) in active duty military personnel.

OBJECTIVE

To examine the effects of massed prolonged exposure therapy (massed therapy), spaced prolonged exposure therapy (spaced therapy), present-centered therapy (PCT), and a minimal-contact control (MCC) on PTSD severity.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial conducted at Fort Hood, Texas, from January 2011 through July 2016 and enrolling 370 military personnel with PTSD who had returned from Iraq, Afghanistan, or both. Final follow-up was July 11, 2016.

INTERVENTIONS

Prolonged exposure therapy, cognitive behavioral therapy involving exposure to trauma memories/reminders, administered as massed therapy (n = 110; 10 sessions over 2 weeks) or spaced therapy (n = 109; 10 sessions over 8 weeks); PCT, a non-trauma-focused therapy involving identifying/discussing daily stressors (n = 107; 10 sessions over 8 weeks); or MCC, telephone calls from therapists (n = 40; once weekly for 4 weeks).

MAIN OUTCOMES AND MEASURES

Outcomes were assessed before and after treatment and at 2-week, 12-week, and 6-month follow-up. Primary outcome was interviewer-assessed PTSD symptom severity, measured by the PTSD Symptom Scale-Interview (PSS-I; range, 0-51; higher scores indicate greater PTSD severity; MCID, 3.18), used to assess efficacy of massed therapy at 2 weeks posttreatment vs MCC at week 4; noninferiority of massed therapy vs spaced therapy at 2 weeks and 12 weeks posttreatment (noninferiority margin, 50% [2.3 points on PSS-I, with 1-sided α = .05]); and efficacy of spaced therapy vs PCT at posttreatment.

RESULTS

Among 370 randomized participants, data were analyzed for 366 (mean age, 32.7 [SD, 7.3] years; 44 women [12.0%]; mean baseline PSS-I score, 25.49 [6.36]), and 216 (59.0%) completed the study. At 2 weeks posttreatment, mean PSS-I score was 17.62 (mean decrease from baseline, 7.13) for massed therapy and 21.41 (mean decrease, 3.43) for MCC (difference in decrease, 3.70 [95% CI,0.72 to 6.68]; P = .02). At 2 weeks posttreatment, mean PSS-I score was 18.03 for spaced therapy (decrease, 7.29; difference in means vs massed therapy, 0.79 [1-sided 95% CI, -∞ to 2.29; P = .049 for noninferiority]) and at 12 weeks posttreatment was 18.88 for massed therapy (decrease, 6.32) and 18.34 for spaced therapy (decrease, 6.97; difference, 0.55 [1-sided 95% CI, -∞ to 2.05; P = .03 for noninferiority]). At posttreatment, PSS-I scores for PCT were 18.65 (decrease, 7.31; difference in decrease vs spaced therapy, 0.10 [95% CI, -2.48 to 2.27]; P = .93).

CONCLUSIONS AND RELEVANCE

Among active duty military personnel with PTSD, massed therapy (10 sessions over 2 weeks) reduced PTSD symptom severity more than MCC at 2-week follow-up and was noninferior to spaced therapy (10 sessions over 8 weeks), and there was no significant difference between spaced therapy and PCT. The reductions in PTSD symptom severity with all treatments were relatively modest, suggesting that further research is needed to determine the clinical importance of these findings.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01049516.

Brief cognitive-behavioral therapy effects on post-treatment suicide attempts in a military sample: results of a randomized clinical trial with 2-year follow-up

OBJECTIVE

The authors evaluated the effectiveness of brief cognitive-behavioral therapy (CBT) for the prevention of suicide attempts in military personnel.

METHOD

In a randomized controlled trial, active-duty Army soldiers at Fort Carson, Colo., who either attempted suicide or experienced suicidal ideation with intent, were randomly assigned to treatment as usual (N=76) or treatment as usual plus brief CBT (N=76). Assessment of incidence of suicide attempts during the follow-up period was conducted with the Suicide Attempt Self-Injury Interview. Inclusion criteria were the presence of suicidal ideation with intent to die during the past week and/or a suicide attempt within the past month. Soldiers were excluded if they had a medical or psychiatric condition that would prevent informed consent or participation in outpatient treatment, such as active psychosis or mania. To determine treatment efficacy with regard to incidence and time to suicide attempt, survival curve analyses were conducted. Differences in psychiatric symptoms were evaluated using longitudinal random-effects models.

RESULTS

From baseline to the 24-month follow-up assessment, eight participants in brief CBT (13.8%) and 18 participants in treatment as usual (40.2%) made at least one suicide attempt (hazard ratio=0.38, 95% CI=0.16-0.87, number needed to treat=3.88), suggesting that soldiers in brief CBT were approximately 60% less likely to make a suicide attempt during follow-up than soldiers in treatment as usual. There were no between-group differences in severity of psychiatric symptoms.

CONCLUSIONS

Brief CBT was effective in preventing follow-up suicide attempts among active-duty military service members with current suicidal ideation and/or a recent suicide attempt.

Randomized trial of behavior therapy for adults with Tourette syndrome

CONTEXT

Tics in Tourette syndrome begin in childhood, peak in early adolescence, and often decrease by early adulthood. However, some adult patients continue to have impairing tics. Medications for tics are often effective but can cause adverse effects. Behavior therapy may offer an alternative but has not been examined in a large-scale controlled trial in adults.

OBJECTIVE

To test the efficacy of a comprehensive behavioral intervention for tics in adults with Tourette syndrome of at least moderate severity.

DESIGN

A randomized controlled trial with posttreatment evaluations at 3 and 6 months for positive responders.

SETTING

Three outpatient research clinics.

PATIENTS

Patients (N = 122; 78 males; age range, 16-69 years) with Tourette syndrome or chronic tic disorder were recruited between December 27, 2005, and May 21, 2009.

INTERVENTIONS

Patients received 8 sessions of comprehensive behavioral intervention for tics or 8 sessions of supportive treatment for 10 weeks. Patients with a positive response were given 3 monthly booster sessions.

MAIN OUTCOME MEASURES

Total tic score on the Yale Global Tic Severity Scale and the Clinical Global Impression-Improvement scale rated by a clinician masked to treatment assignment.

RESULTS

Behavior therapy was associated with a significantly greater mean (SD) decrease on the Yale Global Tic Severity Scale (24.0 [6.47] to 17.8 [7.32]) from baseline to end point compared with the control treatment (21.8 [6.59] to 19.3 [7.40]) (P < .001; effect size = 0.57). Twenty-four of 63 patients (38.1%) were rated as much improved or very much improved on the Clinical Global Impression-Improvement scale compared with 4 of 63 (6.4%) in the control group (P < .001). Attrition was 13.9%, with no difference across groups. Patients receiving behavior therapy who were available for assessment at 6 months after treatment showed continued benefit.

CONCLUSION

Comprehensive behavior therapy is a safe and effective intervention for adults with Tourette syndrome.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00231985.

Effect of Group vs Individual Cognitive Processing Therapy in Active-Duty Military Seeking Treatment for Posttraumatic Stress Disorder: A Randomized Clinical Trial

IMPORTANCE

Cognitive processing therapy (CPT), an evidence-based treatment for posttraumatic stress disorder (PTSD), has not been tested as an individual treatment among active-duty military. Group CPT may be an efficient way to deliver treatment.

OBJECTIVE

To determine the effects of CPT on PTSD and co-occurring symptoms and whether they differ when administered in an individual or a group format.

DESIGN, SETTING, AND PARTICIPANTS

In this randomized clinical trial, 268 active-duty servicemembers consented to assessment at an army medical center from March 8, 2012, to September 23, 2014, and were randomized to group or individual CPT. Inclusion criteria were PTSD after military deployment and stable medication therapy. Exclusion criteria consisted of suicidal or homicidal intent or psychosis. Data collection was completed on June 15, 2015. Analysis was based on intention to treat.

INTERVENTIONS

Participants received CPT (the version excluding written accounts) in 90-minute group sessions of 8 to 10 participants (15 cohorts total; 133 participants) or 60-minute individual sessions (135 participants) twice weekly for 6 weeks. The 12 group and individual sessions were conducted concurrently.

MAIN OUTCOMES AND MEASURES

Primary measures were scores on the Posttraumatic Symptom Scale-Interview Version (PSS-I) and the stressor-specific Posttraumatic Stress Disorder Checklist (PCL-S); secondary measures were scores on the Beck Depression Inventory-II (BDI-II) and the Beck Scale for Suicidal Ideation (BSSI). Assessments were completed by independent evaluators masked to treatment condition at baseline and 2 weeks and 6 months after treatment.

RESULTS

Among the 268 participants (244 men [91.0%]; 24 women [9.0%]; mean [SD] age, 33.2 [7.4] years), improvement in PTSD severity at posttreatment was greater when CPT was administered individually compared with the group format (mean [SE] difference on the PSS-I, -3.7 [1.4]; Cohen d = 0.6; P = .006). Significant improvements were maintained with the individual (mean [SE] PSS-I, -7.8 [1.0]; Cohen d = 1.3; mean [SE] PCL-S, -12.6 [1.4]; Cohen d = 1.2) and group (mean [SE] PSS-I, -4.0 [0.97]; Cohen d = 0.7; mean [SE] PCL-S, -6.3 [1.4]; Cohen d = 0.6) formats, with no differences in remission or severity of PTSD at the 6-month follow-up. Symptoms of depression and suicidal ideation did not differ significantly between formats.

CONCLUSIONS AND RELEVANCE

Individual treatment resulted in greater improvement in PTSD severity than group treatment. Depression and suicidal ideation improved equally with both formats. However, even among those receiving individual CPT, approximately 50% still had PTSD and clinically significant symptoms. In the military population, improving existing treatments such as CPT or developing new treatments is needed.

TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT02173561.

Expression and function of CD4 in a murine T-cell hybridoma

The CD4 (T4) antigen was originally described as a phenotypic marker specific for helper T cells, and has recently been shown to be the receptor for the human immunodeficiency virus (HIV). Functional studies using monoclonal antibodies directed at CD4 and major histocompatibility complex (MHC) class II molecules led to the suggestion that CD4 binds to the MHC class II molecules expressed on stimulator cells, enhancing T-cell responsiveness by increasing the avidity of T cell-stimulator cell interaction and/or by transmitting a positive intracellular signal. But recent evidence that antibodies to CD4 inhibit T-cell responsiveness in the absence of any putative ligand for CD4 has been interpreted as suggesting that antibody-mediated inhibition may involve the transmission of a negative signal via the CD4 molecule instead. We have infected a murine T-cell hybridoma that produces interleukin 2 (IL-2) in response to human class II HLA-DR antigens with a retroviral vector containing CD4 cDNA. The resulting CD4-expressing hybridoma cell lines produce 6- to 20-fold more IL-2 in response to HLA-DR antigens than control cell lines. Furthermore, when antigen levels are suboptimal, the response of the cell lines is entirely CD4-dependent. The data presented here clearly demonstrate that CD4 can enhance T-cell responsiveness and may be crucial in the response to suboptimal levels of antigen.

Habit reversal versus supportive psychotherapy for Tourette's disorder: a randomized controlled trial

OBJECTIVE

The authors investigated the efficacy of habit reversal for Tourette's disorder, which is characterized by multiple motor and vocal tics.

METHOD

Thirty-two patients with Tourette's disorder were randomly assigned to 14 sessions of either habit reversal or supportive psychotherapy. Habit reversal consisted of awareness training, self-monitoring, relaxation training, competing response training, and contingency management. Changes in severity of Tourette's disorder and psychosocial impairment were investigated over the course of the 14-session treatment for the 29 patients who completed at least eight treatment sessions.

RESULTS

In contrast to the 13 patients in the supportive psychotherapy group, the 16 patients in the habit reversal group improved significantly. The habit reversal patients remained significantly improved over pretreatment at 10-month follow-up.

CONCLUSIONS

Habit reversal may be an effective behavioral treatment for Tourette's disorder.

A transgene containing lacZ inserted into the dystonia locus is expressed in neural tube

The site of integration of transgenes in the host genome can affect levels of expression and occasionally confer ectopic patterns of expression on otherwise tissue-specific genes. We describe here a line of mice in which an hsp68-lacZ transgene is expressed in unstressed developing neural tissue and where the transgene insertion has caused a mutation of a neural tissue-specific gene, dystonia musculorum (dt). This coincidence suggests that expression of the hsp68-lacZ construct may be controlled directly by cis-acting regulatory sequences that normally control the developmental expression of the dt gene. Such constructs may serve as useful tools for identifying new tissue-specific enhancers and their associated genes.

Synergistic T cell activation via the physiological ligands for CD2 and the T cell receptor

T cells may be activated either by the antigen-specific T cell receptor (TCR)-CD3 complex or the cell surface receptor CD2. A natural ligand for CD2 has been found to be lymphocyte function-associated antigen 3 (LFA-3), a widely distributed cell surface glycoprotein. To investigate the interaction of these two pathways, we have expressed the cDNA encoding the human CD2 molecule in a murine T cell hybridoma that produces IL-2 in response to HLA-DR antigens. Expression of the CD2 molecule markedly enhances IL-2 production in response to LFA-3+ antigen-bearing stimulator cells, and this stimulation is inhibited by anti-CD2 and anti-LFA-3 mAb. To further define the role of LFA-3 in antigen-dependent T cell activation, we have studied the ability of the purified ligands of CD2 and the TCR to stimulate the hybridoma. Neither liposomes containing purified HLA-DR antigens nor liposomes containing purified LFA-3 were able to stimulate the parent or the CD2+ hybridoma. However, liposomes containing both purified LFA-3 and HLA-DR, the physiological ligands for CD2 and the TCR, respectively, stimulate IL-2 production by the CD2+ but not the parent hybridoma, suggesting that complementary interactions between the TCR-CD3 complex and the CD2 pathway may regulate lymphocyte activation. To determine whether the CD2/LFA-3 interaction participates in cell-cell adhesion and provides an activation signal, we have constructed a cytoplasmic deletion mutant of CD2, CD2 delta B, in which the COOH-terminal 100 amino acids of CD2 have been replaced with a serine. Hybridomas expressing the CD2 delta B molecule were examined. Deletion of the cytoplasmic domain of CD2 did not alter binding of LFA-3 but eliminated the ability of CD2 to increase the response of the hybridoma to liposomes containing both HLA-DR and LFA-3, demonstrating that adhesion of LFA-3 to CD2 alone was insufficient for activation, and that the cytoplasmic domain was required for LFA-3 stimulation through the CD2 molecule. T cells may be activated by purified LFA-3 binding to CD2 and the TCR interacting with its ligand, and these signals appear to be synergistic for the T cell. These results suggest that the CD2/LFA-3 interaction not only plays a role in cell-cell adhesion but provides a stimulatory signal for T cell activation.

A randomized clinical trial of group cognitive processing therapy compared with group present-centered therapy for PTSD among active duty military personnel

OBJECTIVE

To determine whether group therapy improves symptoms of posttraumatic stress disorder (PTSD), this randomized clinical trial compared efficacy of group cognitive processing therapy (cognitive only version; CPT-C) with group present-centered therapy (PCT) for active duty military personnel.

METHOD

Patients attended 90-min groups twice weekly for 6 weeks at Fort Hood, Texas. Independent assessments were administered at baseline, weekly before sessions, and 2 weeks, 6 months, and 12 months posttreatment. A total of 108 service members (100 men, 8 women) were randomized. Inclusion criteria included PTSD following military deployment and medication stability. Exclusion criteria included suicidal/homicidal intent or other severe mental disorders requiring immediate treatment. Follow-up assessments were administered regardless of treatment completion. Primary outcome measures were the PTSD Checklist (Stressor Specific Version; PCL-S) and Beck Depression Inventory-II. The Posttraumatic Stress Symptom Interview (PSS-1) was a secondary measure.

RESULTS

Both treatments resulted in large reductions in PTSD severity, but improvement was greater in CPT-C. CPT-C also reduced depression, with gains remaining during follow-up. In PCT, depression only improved between baseline and before Session 1. There were few adverse events associated with either treatment.

CONCLUSIONS

Both CPT-C and PCT were tolerated well and reduced PTSD symptoms in group format, but only CPT-C improved depression. This study has public policy implications because of the number of active military needing PTSD treatment, and demonstrates that group format of treatment of PTSD results in significant improvement and is well tolerated. Group therapy may an important format in settings in which therapists are limited.

Phosphoinositide-specific phospholipase C-delta 1 binds with high affinity to phospholipid vesicles containing phosphatidylinositol 4,5-bisphosphate

We studied the binding of phosphoinositide-specific phospholipase C-delta 1 (PLC-delta) to vesicles containing the negatively charged phospholipids phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylserine (PS). PLC-delta did not bind significantly to large unilamellar vesicles formed from the zwitterionic lipid phosphatidylcholine (PC) but bound strongly to vesicles formed from mixtures of PC and PIP2. The apparent association constant for the putative 1:1 complex formed between PLC-delta and PIP2 was Ka congruent to 10(5) M-1. The binding strength increased further (Ka congruent to 10(6) M-1) when the vesicles also contained 30% PS. High-affinity binding of PLC-delta to PIP2 did not require Ca2+. PLC-delta bound only weakly to vesicles formed from mixtures of PC and either PS or phosphatidylinositol (PI); binding increased as the mole fraction of acidic lipid in the vesicles increased. We also studied the membrane binding of a small basic peptide that corresponds to a conserved region of PLC. Like PLC-delta, the peptide bound weakly to vesicles containing monovalent negatively charged lipids; unlike PLC-delta, it did not bind strongly to vesicles containing PIP2. Our data suggest that a significant fraction of the PLC-delta in a cell could be bound to PIP2 on the cytoplasmic surface of the plasma membrane.

Early Functional Loading of Brånemark Dental Implants: 5-Year Clinical Follow-up Study

BACKGROUND

Short-term clinical studies have indicated the possibility of one-stage surgery and early loading of machined titanium implants. However, long-term data comparing the outcome to the conventional two-stage technique are missing.

PURPOSE

A clinical and radiographic study was performed to compare the outcome of oral rehabilitation of the edentulous mandible by fixed suprastructures connected to implants installed according to either (1) a one-stage surgical procedure and early loading (experimental group--EG) or (2) the original two-stage concept (reference group--RG). The EG and RG comprised 16 and 11 subjects, respectively.

MATERIALS AND METHODS

The following specific inclusion criterion were adopted: (1) all patients had to consider themselves to be in good general health, (2) the amount of bone had to enable the installation of five to six, at least 10-mm long fixtures (Mk II fixtures; Nobel Biocare AB, Göteborg, Sweden) between the mental foramina, and (3) the patients had to be available for the follow-up and maintenance program. A total of 88 implants were placed in the EG compared to 30 in the RG. In the EG, fixed appliances were connected to the implants within 20 days following implant installation while the fixed appliances in the RG were connected about 4 months following fixture installation. At delivery of the suprastructures, all patients were radiographically examined, an examination that was repeated at the 18- and 60-month follow-ups.

RESULTS

The analysis of the radiographs from the EG disclosed that during the observation period, between 18 and 60 months, the mean loss of bone support amounted to 0.2 mm (SD = 0.4). The corresponding value observed in the RG was 0.0 mm (SD = 0.5). During the 60-month observation period, no fixture was lost in any of the two groups examined. The implants under study as well as those in the reference material were at all observation intervals found to be clinically stable.

CONCLUSIONS

This clinical study demonstrated that it is, at least based on a 5-year observation period, possible to successfully load via a permanent fixed rigid cross-arch suprastructure titanium dental implants soon after installation. However, such a treatment approach has to be strictly limited to the interforamina area of the edentulous mandible. Furthermore, the bone resorption was found to be within the same range around such implants as around implants installed and loaded according to the original two-stage protocol.

Diminished support for linkage between manic depressive illness and X-chromosome markers in three Israeli pedigrees

The hypothesis that chromosomal region Xq27-28 harbours a gene for manic-depression has been a focus of interest in human genetics. X-linked inheritance of manic depressive illness has been re-examined in 3 multigeneration Israeli kindreds. Extension and re-evaluation of pedigree data, including new individuals, diagnostic follow-up, and analysis with DNA markers, shows greatly diminished support for linkage to Xq28. The peak lod scores in two of the pedigrees have dropped several lod units to clearly negative values at the RCP-F8-G6PD gene cluster. On the other hand, positive lod scores (Zmax = 2.09) are sustained in another pedigree at the same map location. None of the pedigrees show linkage to more proximal markers, including the Xq27 locus DXS98. Our analysis underscores the uncertainties in studying complex disorders.

A complete genome screen for genes predisposing to severe bipolar disorder in two Costa Rican pedigrees

Bipolar mood disorder (BP) is a debilitating syndrome characterized by episodes of mania and depression. We designed a multistage study to detect all major loci predisposing to severe BP (termed BP-I) in two pedigrees drawn from the Central Valley of Costa Rica, where the population is largely descended from a few founders in the 16th-18th centuries. We considered only individuals with BP-I as affected and screened the genome for linkage with 473 microsatellite markers. We used a model for linkage analysis that incorporated a high phenocopy rate and a conservative estimate of penetrance. Our goal in this study was not to establish definitive linkage but rather to detect all regions possibly harboring major genes for BP-I in these pedigrees. To facilitate this aim, we evaluated the degree to which markers that were informative in our data set provided coverage of each genome region; we estimate that at least 94% of the genome has been covered, at a predesignated threshold determined through prior linkage simulation analyses. We report here the results of our genome screen for BP-I loci and indicate several regions that merit further study, including segments in 18q, 18p, and 11p, in which suggestive lod scores were observed for two or more contiguous markers. Isolated lod scores that exceeded our thresholds in one or both families also occurred on chromosomes 1, 2, 3, 4, 5, 7, 13, 15, 16, and 17. Interesting regions highlighted in this genome screen will be followed up using linkage disequilibrium (LD) methods.

Monoclonal antibody and ligand binding sites of the T cell erythrocyte receptor (CD2)

The human T cell erythrocyte receptor (CD2 antigen) allows thymocytes and mature T cells to adhere to thymic epithelium and target cells through a cell surface protein, LFA-3 (refs 1-6). Monoclonal antibodies recognizing CD2 can either block adhesion or, in certain combinations, induce an antigen-independent T cell activation. We have identified the binding sites for 16 monoclonal antibodies against CD2 by a rapid and generally applicable mutational analysis. The binding sites fall in three discrete regions: antibodies that participate in activation and block erythrocyte adhesion bind to the first region; antibodies that block adhesion bind to the second region; and antibodies that participate in activation but do not block adhesion bind to the third region. A large number of mutations selected for loss of antibody reactivity in the first two regions also weaken the CD2-LFA-3 interaction. Good agreement was observed between mutational lesions blocking LFA-3 binding and lesions blocking binding by activating antibodies, which supports the view that such antibodies induce T cell activation by mimicking the effect of LFA-3 binding. CD2 sequences that participate in LFA-3 binding correspond to immunoglobulin variable region hypervariable sequences when the homologous domains are aligned.

Human impacts on the rates of recent, present, and future bird extinctions

Unqualified, the statement that approximately 1.3% of the approximately 10,000 presently known bird species have become extinct since A.D. 1500 yields an estimate of approximately 26 extinctions per million species per year (or 26 E/MSY). This is higher than the benchmark rate of approximately 1 E/MSY before human impacts, but is a serious underestimate. First, Polynesian expansion across the Pacific also exterminated many species well before European explorations. Second, three factors increase the rate: (i) The number of known extinctions before 1800 is increasing as taxonomists describe new species from skeletal remains. (ii) One should calculate extinction rates over the years since taxonomists described the species. Most bird species were described only after 1850. (iii) Some species are probably extinct; there is reluctance to declare them so prematurely. Thus corrected, recent extinction rates are approximately 100 E/MSY. In the last decades, the rate is <50 E/MSY, but would be 150 E/MSY were it not for conservation efforts. Increasing numbers of extinctions are on continents, whereas previously most were on islands. We predict a 21st century rate of approximately 1,000 E/MSY. Extinction threatens 12% of bird species; another 12% have small geographical ranges and live where human actions rapidly destroy their habitats. If present forest losses continue, extinction rates will reach 1,500 E/MSY by the century's end. Invasive species, expanding human technologies, and global change will harm additional species. Birds are poor models for predicting extinction rates for other taxa. Human actions threaten higher fractions of other well known taxa than they do birds. Moreover, people take special efforts to protect birds.