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Biomedical subjects

A Ehlers

Publications and source records attributed to A Ehlers.

At least 19 recordsLinked to original sources
PubMed2001

Characterization of clustered MHC-linked olfactory receptor genes in human and mouse.

Olfactory receptor (OR) loci frequently cluster and are present on most human chromosomes. They are members of the seven transmembrane receptor (7-TM) superfamily and, as such, are part of one of the largest mammalian multigene families, with an estimated copy number of up to 1000 ORs per haploid genome. As their name implies, ORs are known to be involved in the perception of odors and possibly also in other, nonolfaction-related, functions. Here, we report the characterization of ORs that are part of the MHC-linked OR clusters in human and mouse (partial sequence only). These clusters are of particular interest because of their possible involvement in olfaction-driven mate selection. In total, we describe 50 novel OR loci (36 human, 14 murine), making the human MHC-linked cluster the largest sequenced OR cluster in any organism so far. Comparative and phylogenetic analyses confirm the cluster to be MHC-linked but divergent in both species and allow the identification of at least one ortholog that will be useful for future regulatory and functional studies. Quantitative feature analysis shows clear evidence of duplications of blocks of OR genes and reveals the entire cluster to have a genomic environment that is very different from its neighboring regions. Based on in silico transcript analysis, we also present evidence of extensive long-distance splicing in the 5'-untranslated regions and, for the first time, of alternative splicing within the single coding exon of ORs. Taken together with our previous finding that ORs are also polymorphic, the presented data indicate that the expression, function, and evolution of these interesting genes might be more complex than previously thought.

Amino Acid Sequence↗
PubMed2000

Heartbeat perception in panic disorder: a reanalysis.

This article describes a reanalysis of seven studies on heart beat perception (HBP) in panic disorder. The pooled sample had 709 participants from eight diagnostic categories. Accurate HBP was uncommon, but more prevalent among panic disorder patients than among healthy controls, depressed patients, patients with palpitations and individuals with infrequent panic attacks. No differences were found between panic disorder patients and patients with other anxiety disorders. Accurate perceivers had higher anxiety sensitivity scores than inaccurate perceivers. The data remain inconclusive as to whether perceived heart rate is correlated with anxiety in inaccurate perceivers. Physical exercise, distraction, variations in instructions and treatment each influenced HBP. However, the influence was different than previously thought. Finally, it is suggested that HBP may be understood in terms of schema-guided information processing.

Adult↗
PubMed2000

Dysfunctional meaning of posttraumatic intrusions in chronic PTSD.

The paper suggests that the negative idiosyncratic meaning of posttraumatic intrusions (e.g., 'I am going crazy') and cognitive strategies intended to control the intrusions play a major role in maintaining posttraumatic stress disorder. Two studies of 159 and 138 motor vehicle accidents survivors showed that the dysfunctional meaning of intrusions explained a proportion of the variance of the intrusion-related distress, strategies used to end the intrusions, and PTSD severity that was not explained by intrusion frequency, accident severity, or by general catastrophic thoughts when anxious. Rumination, thought suppression, and distraction when having intrusions showed substantial correlations with PTSD severity, as did avoidance of reminders of the accident. The results have implications for the treatment of chronic PTSD.

Accidents, Traffic↗
PubMed2000

A cognitive model of posttraumatic stress disorder.

Posttraumatic stress disorder (PTSD) is a common reaction to traumatic events. Many people recover in the ensuing months, but in a significant subgroup the symptoms persist, often for years. A cognitive model of persistence of PTSD is proposed. It is suggested that PTSD becomes persistent when individuals process the trauma in a way that leads to a sense of serious, current threat. The sense of threat arises as a consequence of: (1) excessively negative appraisals of the trauma and/or its sequelae and (2) a disturbance of autobiographical memory characterised by poor elaboration and contextualization, strong associative memory and strong perceptual priming. Change in the negative appraisals and the trauma memory are prevented by a series of problematic behavioural and cognitive strategies. The model is consistent with the main clinical features of PTSD, helps explain several apparently puzzling phenomena and provides a framework for treatment by identifying three key targets for change. Recent studies have provided preliminary support for several aspects of the model.

Adaptation, Psychological↗
PubMed2000

Social anxiety and self-impression: cognitive preparation enhances the beneficial effects of video feedback following a stressful social task.

Negative and distorted images of the observable self are important in the development and maintenance of social phobia. Previous research has shown that video feedback has potential to correct the distorted self-perception [Rapee, R. M. & Hayman, K. (1996). The effects of video feedback on the self-evaluation of performance in socially anxious subjects. Behaviour Research and Therapy, 34, 315-322]. The present experiment investigated whether the construction of a self-image prior to viewing the video may enhance the therapeutic effects of video feedback. High and low socially anxious individuals gave a speech and then viewed the video of their performance. Half of the sample were given cognitive preparation prior to viewing the video. Cognitive preparation involved asking participants to (1) predict in detail what they will see in the video, (2) form an image of themselves giving the speech and (3) watch the video as though they were watching a stranger. Participants who received cognitive preparation prior to the video feedback made higher ratings of their overall performance and of specific aspects of their performance compared to those who were not given cognitive preparation and compared to the same ratings made prior to the video feedback. These results suggest that the therapeutic effects of video feedback can be enhanced by careful cognitive preparation which maximises the perceived discrepancy between self and video images.

Adolescent↗
PubMed2000

Polymorphisms in olfactory receptor genes: a cautionary note.

The hundreds of human olfactory receptor (OR) genes are organized into clusters occurring on nearly every chromosome. Although their sequences are not always closely related, they share stretches of considerable similarity, both at the amino acid and nucleotide levels. We demonstrate here that an HLA complex-linked OR sequence, FAT11, for which recently a number of alleles have been claimed within the Hutterites, contains sequences derived from two closely related, linked OR genes, hs6M1-12 and hs6M1-16. Instead of indicating a difference between alleles of a given locus, two of the polymorphisms described for FAT11 (at amino acids 48 and 220 of the deduced protein sequence, respectively) may in fact reflect distinct sequences of hs6M1-12 and a further, closely related HLA-linked OR locus, hs6M1-13P. As a consequence, recombination rates in Hutterites in the region telomeric of HLA-G may have to be reconsidered.

Amino Acid Substitution↗
PubMed2000

MHC-linked olfactory receptor loci exhibit polymorphism and contribute to extended HLA/OR-haplotypes.

Clusters of olfactory receptor (OR) genes are found on most human chromosomes. They are one of the largest mammalian multigene families. Here, we report a systematic study of polymorphism of OR genes belonging to the largest fully sequenced OR cluster. The cluster contains 36 OR genes, of which two belong to the vomeronasal 1 (V1-OR) family. The cluster is divided into a major and a minor region at the telomeric end of the HLA complex on chromosome 6. These OR genes could be involved in MHC-related mate preferences. The polymorphism screen was carried out with 13 genes from the HLA-linked OR cluster and three genes from chromosomes 7, 17, and 19 as controls. Ten human cell lines, representing 18 different chromosome 6s, were analyzed. They were from various ethnic origins and exhibited different HLA haplotypes. All OR genes tested, including those not linked to the HLA complex, were polymorphic. These polymorphisms were dispersed along the coding region and resulted in up to seven alleles for a given OR gene. Three polymorphisms resulted either in stop codons (genes hs6M1-4P, hs6M1-17) or in a 16-bp deletion (gene hs6M1-19P), possibly leading to lack of ligand recognition by the respective receptors in the cell line donors. In total, 13 HLA-linked OR haplotypes could be defined. Therefore, allelic variation appears to be a general feature of human OR genes.

Alleles↗
PubMed2000

Psychological debriefing for road traffic accident victims. Three-year follow-up of a randomised controlled trial.

BACKGROUND: Psychological debriefing is widely used for trauma victims but there is uncertainty about its efficacy. We have previously reported a randomised controlled trial which concluded that at 4 months it was ineffective. AIMS: To evaluate the 3-year outcome in a randomised controlled trial of debriefing for consecutive subjects admitted to hospital following a road traffic accident. METHOD: Patients were assessed in hospital by the Impact of Event Scale (IES), Brief Symptom Inventory (BSI) and questionnaire and re-assessed at 3 months and 3 years. The intervention was psychological debriefing as recommended and described in the literature. RESULTS: The intervention group had a significantly worse outcome at 3 years in terms of general psychiatric symptoms (BSI), travel anxiety when being a passenger, pain, physical problems, overall level of functioning, and financial problems. Patients who initially had high intrusion and avoidance symptoms (IES) remained symptomatic if they had received the intervention, but recovered if they did not receive the intervention. CONCLUSIONS: Psychological debriefing is ineffective and has adverse long-term effects. It is not an appropriate treatment for trauma victims.

Accidents, Traffic↗
PubMed2000

Posttraumatic stress disorder following political imprisonment: the role of mental defeat, alienation, and perceived permanent change.

An interview study of 81 former political prisoners investigated whether posttraumatic stress disorder (PTSD) is related to the way individuals process the prison experience. In contrast to participants without PTSD, those with chronic or remitted PTSD were more likely to perceive mental defeat and an overall feeling of alienation from other people. Chronic PTSD was also related to perceived negative and permanent change in their personalities or life aspirations. The groups did not differ in their attempts to gain control during imprisonment. Evidence for a relationship between political commitment and PTSD was mixed. The results suggest that mental defeat, alienation, and permanent change are related to PTSD after interpersonal trauma and may need to be addressed in treatment.

Adolescent↗
PubMed1999

Cognitive factors involved in the onset and maintenance of posttraumatic stress disorder (PTSD) after physical or sexual assault.

Cognitive factors hypothesised to influence the development and maintenance of PTSD were investigated. 92 assault victims completed questionnaires assessing a range of cognitive variables. Factors relating to onset of PTSD were investigated by comparing victims who did and who did not suffer PTSD. Factors relating to maintenance of PTSD were investigated by comparing victims who had recovered from PTSD with victims who had persistent PTSD. Cognitive factors associated with both onset and maintenance of PTSD were: appraisal of aspects of the assault itself (mental defeat, mental confusion, appraisal of emotions); appraisal of the sequelae of the assault (appraisal of symptoms, perceived negative responses of others, permanent change); dysfunctional strategies (avoidance/safety seeking) and global beliefs impacted by assault. Cognitive factors that were associated only with the onset of PTSD were: detachment during assault; failure to perceive positive responses from others and mental undoing. Relationships between the cognitive variables and PTSD remained significant when variations in perceived and objective assault severity were statistically controlled. The cognitive factors identified in the study may contribute to PTSD directly, by generating a sense of ongoing threat, or indirectly, by motivating cognitive and behavioural strategies that prevent recovery, or by affecting the nature of the traumatic memory.

Adult↗
PubMed1999

PTSD symptoms, response to intrusive memories and coping in ambulance service workers.

OBJECTIVES: To examine the relationship of coping strategies and responses to intrusive memories with post-traumatic stress disorder (PTSD) and other psychiatric symptoms in ambulance service workers. METHOD: Fifty-six ambulance service workers describe the most distressing aspects of their work and completed questionnaires designed to measure their coping strategies in dealing with distressing incidents. They also described their intrusive memories of particularly distressing incidents and completed a questionnaire designed to measure their interpretation of these intrusions and their responses to them. In addition, they completed the Post-traumatic Stress Symptom Scale (PSS; Foa, Riggs, Dancu & Rothbaum, 1993) and the General Health Questionnaire (GHQ; Goldberg & Hiller, 1979). RESULTS: Of the participants, 21% met DSM-III-R criteria for PTSD, and 22% met GHQ screening criteria for psychiatric symptoms. Wishful thinking and mental disengagement when confronted with critical incidents at work, negative interpretations of intrusive memories, and maladaptive responses to these memories (rumination, suppression and dissociation) correlated with PTSD severity. CONCLUSION: The results are consistent with the hypothesis that coping strategies and responses to intrusive memories that prevent emotional processing of the distressing event maintain PTSD. They also support Ehlers & Steil's (1995) hypotheses about the role of negative interpretations of post-traumatic intrusions in PTSD. A substantial subgroup of emergency service personnel may need support in processing distressing incidents at work and may benefit from information that normalizes post-traumatic symptoms such as intrusions.

Adaptation, Psychological↗
PubMed1998

Predicting response to exposure treatment in PTSD: the role of mental defeat and alienation.

Not all patients with posttraumatic stress disorder benefit from exposure treatment. The present paper describes two cognitive dimensions that are related to inferior response to exposure in rape victims. First, individuals whose memories during relieving of the trauma reflected mental defeat or the absence of mental planning showed little improvement. Second, inferior outcome was correlated with an overall feeling of alienation or permanent change following the trauma. These results are based on blind ratings of transcripts of exposure treatment sessions from 10 women with good outcome and 10 women with inferior outcome. Patients in the two groups were matched for initial symptom severity and were comparable in many aspects of the assault. Patients who experienced mental defeat, alienation, or permanent change may require cognitive restructuring in addition to exposure.

Adult↗
PubMed1998

Dysfunctional cognitions and adult psychological functioning in child sexual abuse survivors.

Two studies explored the relationship between cognitions and long-term symptoms in adult child sexual abuse (CSA) survivors. In Study 1, an American sample of 43 survivors completed questionnaires assessing attributional style and dysfunctional beliefs in cognitive themes affected by victimization, as well as measures of posttraumatic symptoms. Survivors' attributions of negative events were more internal, stable, and global than those of 29 comparison subjects without a history of CSA. However, only the globality scale was significantly related with severity of long-term symptoms. High correlations between dysfunctional beliefs concerning safety, trust, esteem, or intimacy, and posttrauma symptoms were found. The latter finding was replicated in Study 2 with a German sample of 35 CSA survivors, even when controlling for frequency of abuse.

Adult↗
PubMed1998

Psychological predictors of chronic posttraumatic stress disorder after motor vehicle accidents.

A prospective longitudinal study assessed 967 consecutive patients who attended an emergency clinic shortly after a motor vehicle accident, again at 3 months, and at 1 year. The prevalence of posttraumatic stress disorder (PTSD) was 23.1% at 3 months and 16.5% at 1 year. Chronic PTSD was related to some objective measures of trauma severity, perceived threat, and dissociation during the accident, to female gender, to previous emotional problems, and to litigation. Maintaining psychological factors, that is, negative interpretation of intrusions, rumination, thought suppression, and anger cognitions, enhanced the accuracy of the prediction. Negative interpretation of intrusions, persistent medical problems, and rumination at 3 months were the most important predictors of PTSD symptoms at 1 year. Rumination, anger cognitions, injury severity, and prior emotional problems identified cases of delayed onset.

Accidents, Traffic↗