Event-related potential studies of post-traumatic stress disorder: a critical review and synthesis

Despite the sparseness of the currently available data, there is accumulating evidence of information processing impairment in post-traumatic stress disorder (PTSD). Studies of event-related potentials (ERPs) are the main tool in real time examination of information processing. In this paper, we sought to critically review the ERP evidence of information processing abnormalities in patients with PTSD. We also examined the evidence supporting the existence of a relationship between ERP abnormalities and symptom profiles or severity in PTSD patients. An extensive Medline search was performed. Keywords included PTSD or post-traumatic stress disorder, electrophysiology or EEG, electrophysiology, P50, P100, N100, P2, P200, P3, P300, sensory gating, CNV (contingent negative variation) and MMN (mismatch negativity). We limited the review to ERP adult human studies with control groups which were reported in the English language. After applying our inclusion-exclusion review criteria, 36 studies were included. Subjects exposed to wide ranges of military and civilian traumas were studied in these reports. Presented stimuli were both auditory and visual. The most widely studied components included P300, P50 gating, N100 and P200. Most of the studies reported increased P300 response to trauma-related stimuli in PTSD patients. A smaller group of studies reported dampening of responses or no change in responses to trauma-related and/or unrelated stimuli. P50 studies were strongly suggestive of impaired gating in patients with PTSD. In conclusion, the majority of reports support evidence of information processing abnormalities in patients with PTSD diagnosis. The predominance of evidence suggests presence of mid-latency and late ERP components differences in PTSD patients in comparison to healthy controls. Heterogeneity of assessment methods used contributes to difficulties in reaching firm conclusions regarding the nature of these differences. We suggest that future ERP-PTSD studies utilize standardized assessment scales that provide detailed information regarding the symptom clusters and the degree of symptom severity. This would allow assessment of electrophysiological indices-clinical symptoms relationships. Based on the available data, we suggest that ERP abnormalities in PTSD are possibly affected by the level of illness severity. If supported by future research, ERP studies may be used for both initial assessment and treatment follow-up

Metabolic effects of diets differing in glycaemic index depend on age and endogenous GIP

Aims/hypothesis High- vs low-glycaemic index (GI) diets unfavourably affect body fat mass and metabolic markers in rodents. Different effects of these diets could be age-dependent, as well as mediated, in part, by carbohydrate-induced stimulation of glucose-dependent insulinotrophic polypeptide (GIP) signalling. Methods Young-adult (16 weeks) and aged (44 weeks) male wild-type (C57BL/6J) and GIP-receptor knockout (Gipr −/− ) mice were exposed to otherwise identical high-carbohydrate diets differing only in GI (20–26 weeks of intervention, n = 8–10 per group). Diet-induced changes in body fat distribution, liver fat, locomotor activity, markers of insulin sensitivity and substrate oxidation were investigated, as well as changes in the gene expression of anorexigenic and orexigenic hypothalamic factors related to food intake. Results Body weight significantly increased in young-adult high- vs low-GI fed mice (two-way ANOVA, p < 0.001), regardless of the Gipr genotype. The high-GI diet in young-adult mice also led to significantly increased fat mass and changes in metabolic markers that indicate reduced insulin sensitivity. Even though body fat mass also slightly increased in high- vs low-GI fed aged wild-type mice (p < 0.05), there were no significant changes in body weight and estimated insulin sensitivity in these animals. However, aged Gipr −/− vs wild-type mice on high-GI diet showed significantly lower cumulative net energy intake, increased locomotor activity and improved markers of insulin sensitivity. Conclusions/interpretation The metabolic benefits of a low-GI diet appear to be more pronounced in younger animals, regardless of the Gipr genotype. Inactivation of GIP signalling in aged animals on a high-GI diet, however, could be beneficial

Estimating the regional distribution of men who have sex with men (MSM) based on Internet surveys

<p>Abstract</p> <p>Background</p> <p>Measurement of prevalence and incidence of infections in a hard to reach population like men who have sex with men (MSM) is hampered by its unknown size and regional distribution. Population-based surveys have recently been used to estimate the total number of MSM, but these surveys are usually not large enough to measure regional differences in the proportion of MSM in the population. We explored the use of the proportional regional distribution of participants of large internet-based surveys among MSM from Germany to estimate the regional distribution of MSM in Germany.</p> <p>Methods</p> <p>We compared participants from two separate MSM behavioural surveys with each other and with the distribution of user profiles of the largest contact and dating website for gay and other MSM in Germany in terms of the representativeness of the regional distribution. In addition, we compared the regional distribution of reportedly HIV positive survey participants with the regional distribution of HIV notifications within the national surveillance system that can be attributed to transmission through homosexual contacts.</p> <p>Results</p> <p>Regional distribution of survey participants was almost identical in both surveys, despite little overlap between survey participants. Slight discrepancies between surveys and user profiles could be observed. Proportional regional distribution of survey participants with HIV diagnosis resembled national surveillance data.</p> <p>Conclusion</p> <p>Considering the difficulties to obtain representative data by other sampling methods for "hidden" populations like MSM, internet-based surveys may provide an easy and low cost tool to estimate the regional population distribution – at least in Western post-industrialized countries. Some uncertainties remain about the exact place of residence of MSM in larger cities or catchment areas of these cities. Slightly different results from different datasets may be due to unequal popularity of MSM websites in different regions. The total population size of the MSM population can be estimated based on e.g. data from representative national population surveys. Both estimates can then be combined to calculate the absolute size of regional MSM populations.</p

HIV Risks and Seroprevalence Among Mexican American Injection Drug Users in California

Latinos in the United States are an ethnically diverse group disproportionately affected by HIV/AIDS. We describe HIV seroprevalence, HIV risk behaviors and utilization of health services among Mexican American injection drug users (IDUs) in California (n = 286) and compare them to White (n = 830) and African American (n = 314) IDUs. Study participants were recruited from syringe exchange programs (n = 24) in California. HIV seroprevalence among Mexican Americans (0.5%) was dramatically lower than Whites (5%) and African Americans (8%). Mexican Americans reported fewer sex-related risks than Whites and African Americans though injection-related risks remained high. Compared to Whites, Mexican Americans were more likely to participate in drug treatment during a 6 month period (AOR 1.5, 95% CI 1.1, 2.0) but less likely to receive any health care (AOR 0.6, 95% CI 0.5, 0.8). Exploring cultural and structural factors among Mexican American IDUs may offer new insights into how to maintain low rates of HIV seroprevalence and reduce barriers to health care utilization

Tamoxifen-Independent Recombination in the RIP-CreER Mouse

The inducible Cre-lox system is a valuable tool to study gene function in a spatial and time restricted fashion in mouse models. This strategy relies on the limited background activity of the modified Cre recombinase (CreER) in the absence of its inducer, the competitive estrogen receptor ligand, tamoxifen. The RIP-CreER mouse (Tg (Ins2-cre/Esr1) 1Dam) is among the few available β-cell specific CreER mouse lines and thus it has been often used to manipulate gene expression in the insulin-producing cells of the endocrine pancreas

Do Physicians with Self-Reported Non-English Fluency Practice in Linguistically Disadvantaged Communities?

BackgroundLanguage concordance between physicians and patients may reduce barriers to care faced by patients with limited English proficiency (LEP). It is unclear whether physicians with fluency in non-English languages practice in areas with high concentrations of people with LEP.ObjectiveTo investigate whether physician non-English language fluency is associated with practicing in areas with high concentrations of people with LEP.DesignCross-sectional cohort study.ParticipantsA total of 61,138 practicing physicians no longer in training who participated in the California Medical Board Physician Licensure Survey from 2001-2007.MeasuresSelf-reported language fluency in Spanish and Asian languages. Physician practice ZIP code corresponding to: (1) high concentration of people with LEP and (2) high concentration of linguistically isolated households.MethodsPractice location ZIP code was geocoded with geographic medical service study designations. We examined the unadjusted relationships between physician self-reported fluency in Spanish and selected Asian languages and practice location, stratified by race-ethnicity. We used staged logistic multiple variable regression models to isolate the effect of self-reported language fluency on practice location controlling for age, gender, race-ethnicity, medical specialty, and international medical graduate status.ResultsPhysicians with self-reported fluency in Spanish or an Asian language were more likely to practice in linguistically designated areas in these respective languages compared to those without fluency. Physician fluency in an Asian language [adjusted odds ratio (AOR) = 1.77; 95% confidence intervals (CI): 1.63-1.92] was independently associated with practicing in areas with a high number of LEP Asian speakers. A similar pattern was found for Spanish language fluency (AOR = 1.77; 95% CI: 1.43-1.82) and areas with high numbers of LEP Spanish-speakers. Latino and Asian race-ethnicity had the strongest effect on corresponding practice location, and this association was attenuated by language fluency.ConclusionsPhysicians who are fluent in Spanish or an Asian language are more likely to practice in geographic areas where their potential patients speak the corresponding language

Comparison of deferral rates using a computerized versus written blood donor questionnaire: a randomized, cross-over study [ISRCTN84429599]

BACKGROUND: Self-administered computer-assisted blood donor screening strategies may elicit more accurate responses and improve the screening process. METHODS: Randomized crossover trial comparing responses to questions on a computerized hand-held tool (HealthQuiz, or HQ), to responses on the standard written instrument (Donor Health Assessment Questionnaire, or DHAQ). Randomly selected donors at 133 blood donation clinics in the area of Hamilton, Canada participated from 1995 to 1996. Donors were randomized to complete either the HQ or the DHAQ first, followed by the other instrument. In addition to responses of 'yes' and 'no' on both questionnaires, the HQ provided a response option of 'not sure'. The primary outcome was the number of additional donors deferred by the HQ. RESULTS: A total of 1239 donors participated. Seventy-one potential donors were deferred as a result of responses to the questionnaires; 56.3% (40/71) were deferred by the DHAQ, and an additional 43.7% (31/71) were deferred due to risks identified by the HQ but not by the DHAQ. Fourteen donors self-deferred; 11 indicated on the HQ that they should not donate blood on that day but did not use the confidential self-exclusion option on the DHAQ, and three used the self-exclusion option on the DHAQ but did not indicate that they should not donate blood on the HQ. The HQ identified a blood contact or risk factor for HIV/AIDS or sexually transmitted infection that was not identified by the DHAQ in 0.1% to 2.7% of donors. CONCLUSION: A self-administered computerized questionnaire may increase risk reporting by blood donors

Protective Contributions against Invasive Streptococcus pneumoniae Pneumonia of Antibody and Th17-Cell Responses to Nasopharyngeal Colonisation

The nasopharyngeal commensal bacteria Streptococcus pneumoniae is also a frequent cause of serious infections. Nasopharyngeal colonisation with S. pneumoniae inhibits subsequent re-colonisation by inducing Th17-cell adaptive responses, whereas vaccination prevents invasive infections by inducing antibodies to S. pneumoniae capsular polysaccharides. In contrast, protection against invasive infection after nasopharyngeal colonisation with mutant S. pneumoniae strains was associated with antibody responses to protein antigens. The role of colonisation-induced Th17-cell responses during subsequent invasive infections is unknown. Using mouse models, we show that previous colonisation with S. pneumoniae protects against subsequent lethal pneumonia mainly by preventing bacteraemia with a more modest effect on local control of infection within the lung. Previous colonisation resulted in CD4-dependent increased levels of Th17-cell cytokines during subsequent infectious challenge. However, mice depleted of CD4 cells prior to challenge remained protected against bacteraemia, whereas no protection was seen in antibody deficient mice and similar protection could be achieved through passive transfer of serum. Serum from colonised mice but not antibody deficient mice promoted phagocytosis of S. pneumoniae, and previously colonised mice were able to rapidly clear S. pneumoniae from the blood after intravenous inoculation. Thus, despite priming for a Th17-cell response during subsequent infection, the protective effects of prior colonisation in this model was not dependent on CD4 cells but on rapid clearance of bacteria from the blood by antibody-mediated phagocytosis. These data suggest that whilst nasopharyngeal colonisation induces a range of immune responses, the effective protective responses depend upon the site of subsequent infectio

Characterization of Parameters Required for Effective Use of Tamoxifen-Regulated Recombination

Conditional gene targeting using the Cre-loxp system is a well established technique in numerous in vitro and in vivo systems. Ligand regulated forms of Cre have been increasingly used in these applications in order to gain temporal and spatial control over conditional targeting. The tamoxifen-regulated Cre variant mer-Cre-mer (mCrem) is widely utilized because of its reputation for tight regulation in the absence of its tamoxifen ligand. In the DT40 chicken B cell line, we generated an mCrem-based reversible switch for conditional regulation of a transgene, and in contrast with previous work, observed significant constitutive activity of mCrem. This prompted us to use our system for analysis of the parameters governing tamoxifen-regulated mCrem recombination of a genomic target. We find that robust mCrem expression correlates with a high level of tamoxifen-independent Cre activity, while clones expressing mCrem at the limit of western blot detection exhibit extremely tight regulation. We also observe time and dose-dependent effects on mCrem activity which suggest limitations on the use of conditional targeting approaches for applications which require tight temporal coordination of Cre action within a cell population