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PubMed2001

The utility of dimensional and categorical approaches to understanding dissociation in the eating disorders.

OBJECTIVE: The present study compared levels of dissociation across groups of eating-disordered women, investigating the utility of dimensional and categorical measures of dissociation in understanding diagnoses and behaviours in the eating disorders. METHODS: The Dissociative Experiences Scale (DES-II) was completed by 170 eating-disordered women (drawn from out-patient assessment clinics) and 203 nonclinical women. The clinical group also supplied information regarding eating behaviours and related features (alcohol abuse, reported history of sexual abuse). The DES-II and a subset of its items (DES-Taxon) were used as dimensional and categorical discriminators of the groups and of the presence/absence of specific features and symptoms. RESULTS: When treated as dimensional measures, the DES-II and DES-Taxon had similar levels of clinical utility (particularly discriminating the binge-purge anorexics from the other clinical groups). However, the DES-Taxon was a superior categorical measure, discriminating groups more clearly and predicting the presence of many symptoms and features much more powerfully. CONCLUSIONS: The DES-Taxon is a potentially valuable self-report measure for indicating the level and presence of dissociative psychopathology in the eating disorders. As well as being convenient to administer and score, it has the clinical and research value of indicating those patients in whom treatment might need to include addressing pathological dissociation.

Depersonalization↗
PubMed1999

Schizotypy, dissociative experiences and childhood abuse: relationships among self-report measures.

OBJECTIVES: The traits and experiences that are seen as defining the schizophrenic and the dissociative disorders have been found to be present in continuously variable, non-pathological forms in the general population. Although the theoretical accounts that have been offered for the two kinds of disorder differ radically, there are reasons to expect that the measures that have been developed to assess schizotypal traits and dissociative experiences will be correlated. The aims of this study were to investigate the degree of correlation between measures and the extent to which the covariation can be explained by questionnaire items with similar content and experiences of childhood sexual and physical abuse. DESIGN: Cross-sectional data from self-report measures completed by 224 participants were subjected to multivariate analyses. METHOD: The Dissociative Experiences Scale (DES), three subscales from the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE) and two items assessing childhood abuse were mailed to all adult members of a volunteer participant panel. RESULTS: Moderately large correlations were found between the DES and both the Cognitive Disorganization and the Unusual Experiences subscales of the O-LIFE. These correlations were hardly affected when items with overlapping content were excluded. Hierarchical multiple regression analyses showed that the measures of abuse accounted for small but significant proportions of the variance in both the DES and the Unusual Experiences subscale, but large proportions of the covariation between the measures of dissociative experiences and schizotypy remained unexplained. CONCLUSION: The substantial correlations between measures point to limitations in the discriminant validity of the DES and two of the O-LIFE subscales. Three possible explanations are offered for the observed associations between dissociative experiences and schizotypal traits.

Adult↗
PubMed2005

SCL-90 symptom patterns: indicators of dissociative disorders.

The purpose of this study was to examine the SCL-90 profiles of adult outpatients with and without dissociative disorders. A total of 194 participants were administered the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised (SCID-D-R) and the Symptom Checklist-90 (SCL-90). Patients with dissociative identity disorder (DID) reported significantly higher SCL-90 Global Severity Index (GSI) and individual subscale scores than those without dissociative disorders. It is recommended that patients who are polysymptomatic on the SCL-90 be considered for follow-up dissociative symptom assessment to aid differential diagnosis and to inform subsequent treatment.

Adolescent↗
PubMed2004

The paradox of "detachment disorders": binding-disruptions of dissociative process.

This case is discussed in the contexts of affect theory, attachment theory, and dissociative experience. Dissociative adaptations to living that become entrenched resistances during psychotherapeutic inquiry give way to a scrupulous attention to the characteristics of dissociative experiencing. Somatosensory free association and appreciation of experiential aspects of depersonalization, derealization, and dissociative amnesia open new areas of negotiation between patient and therapist. Paradigms from infant attachment and adult attachment research parsimoniously explicate psychodynamic formulations. "Conflicted interest" and "conflicted disinterest" are proposed to flesh out appreciation of the child's inner experience during Type A and Type C attachment experiences. The Type D attachment style is consistent with a dissociative phenotype. The concept of "isolated subjectivity" can help explain the extent to which individuals both know and don't know about their experience, in the same moment, and without conscious conflict or anxiety.

Affect↗
PubMed2004

Trauma and dissociation in conversion disorder and chronic pelvic pain.

OBJECTIVE: The purpose of this study was to: a) assess the link between sexual and/or physical abuse and dissociation in conversion disorder and chronic pelvic pain patients; and b) assess whether this effect is independent of level of general psychopathology. METHOD: This report examines data from four separate samples. Fifty-two patients with chronic pelvic pain, 61 patients with non-epileptic seizures, and two samples of patients (102 and 54) with predominantly motor or sensory types of conversion disorder were studied. RESULTS: Using point-biserial correlations no compelling evidence for a consistent and positive association of sexual and/or physical abuse with dissociation was found. After statistically controlling for level of psychopathology using multiple regression analyses, in most of the cases the association of abuse with dissociation was no longer statistically significant. Only physical abuse predicted level of somatoform dissociation over and above level of psychopathology. CONCLUSION: In future clinical studies of dissociation in patients with conversion disorder and chronic pelvic pain more complex models may be needed with less exclusive reliance on historical antecedents such as childhood abuse and more emphasis on recent potentially traumatizing experiences or co-morbid psychiatric disorders.

Adult↗
PubMed1993

Dissociative experiences of Vietnam veterans with chronic posttraumatic stress disorder.

Interest in dissociation has been renewed, and its relationship to Post-traumatic Stress Disorder is especially intriguing. In this study 57 consecutively admitted chronic, combat-related Posttraumatic Stress Disorder sufferers were grouped by scores on a dissociative scale (Dissociative Experiences Scale). The three groups (high, medium, and low) were compared on personality measures (MMPI basic scales and subscales, and Millon's MCMI), Posttraumatic Stress Disorder measures, and a psychophysiological index of heart rate under baseline trauma conditions. The results showed that the survivors with more dissociative experiences show distinctive and higher symptom levels--excessive fearfulness, symptoms of strange experiences, and high tonic psychophysiological states--as well as greater severity of ratings of Posttraumatic Stress Disorder (on the Mississippi Scale). The discussion addressed the possible role of dissociation in Posttraumatic Stress Disorder.

Adult↗
PubMed1999

Psychogenic or dissociative fugue: a clinical investigation of five cases.

Dissociative fugue (formerly psychogenic fugue) is a rare and little understood dissociative disorder. Following a review of the pertinent literature, five cases of dissociative fugue are described. These cases were systematically studied with a comprehensive history, mental status examination, physical and neurological evaluation, review of previous medical and psychiatric records, and psychological testing including MMPI, WAIS-R, electroencephalogram, and Dissociative Experiences Scale. An unexpected finding was that, in some cases, associated criminal activity may allow the person with dissociative fugue to continue to function in spite of their loss of memory and original identity.

Adult↗
PubMed2002

Acute dissociative responses in law enforcement officers involved in critical shooting incidents: the clinical and forensic implications.

The authors examine the prevalence of acute traumatic dissociative responses in a group of 115 law enforcement officers involved in critical incidents. Law enforcement officers were retrospectively surveyed for the presence of dissociative symptoms at the time of the critical incident, as well as for the presence of acute stress symptoms and posttraumatic stress symptoms. Results show that 90% of the officers reported experiencing a dissociative response during the critical incident. Thirty percent meet the Dissociative Criterion B of acute stress disorder under the DSM-IV. The mean number of dissociative symptoms in this group was two and one-half. In addition, 19% of the law enforcement officers reported varying forms of memory impairment for details of the incident. There were no reports of amnesia for the entire event. The clinical, forensic, and legal implications of these preliminary findings are discussed in this paper.

Acute Disease↗
PubMedDate not supplied

Dissociation in adults with a diagnosis of substance abuse.

Dissociation is a defence mechanism whereby individuals under stress separate affect and/or behaviour from the normal flow of consciousness. It is common in people who have experienced trauma. A Dissociative Experience Scale was used to study 51 subjects who were members of inpatient or outpatient substance abuse programmes. Thirty per cent of the group scored 15 or higher, suggesting that dissociative events are common in this population. Nurses need to understand the phenomenon of dissociation and the relationship between trauma, dissociation and substance abuse. This will enhance their assessment of patients and increase their knowledge base regarding appropriate treatment.

Adult↗
PubMed1995

Using the SCID-D to assess dissociative identity disorder in adolescents: three case studies.

The authors report on the diagnostic assessment of dissociative identity disorder in three adolescents using the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D; Steinberg, 1993b), a semistructured instrument for the diagnosis and assessment of dissociative symptoms and disorders. Although the SCID-D has received good-to-excellent ratings for reliability and validity in the adult population, these three cases are the first reports of the results of its administration to younger patients. Comparison of the three adolescent SCID-D interviews with findings in adults indicates that the profiles of the five dissociative symptoms measured by the SCID-D are virtually identical in adolescents and adults. The authors conclude with suggestions for future research regarding dissociative symptomatology in adolescents and outcome studies.

Adolescent↗
PubMed1993

Dissociative processes: theoretical underpinnings of a working model for clinician and patient.

Dissociative symptoms are now widely recognized, but they are nevertheless challenging for clinicians and bewildering to patients. The author presents a conceptual framework for understanding dissociative processes, emphasizing discontinuity in experience and delineating various junctures in the unfolding of dissociative episodes. The conceptual framework provides the theoretical underpinnings for a simple schema that can be used to explain dissociation to patients and to help them articulate their dissociative experience.

Consciousness↗
PubMed1996

Complex association and dissociation kinetics of brevetoxin binding to voltage-sensitive rat brain sodium channels.

Brevetoxins bind with high affinity to the voltage-sensitive sodium channel and cause nerve cell depolarization and increased sodium ion conductance. Using 0.6 nM tritium-labeled brevetoxin-3 and freshly prepared synaptosomes from fresh or frozen rat brain, binding results at 6 degrees C fit well to a curve for 2-phase association with 65% of the binding in the rapid phase and t1/2 values of 11 and 74 min for the rapid and slow phases, respectively. Both phases were accelerated at higher toxin concentrations, binding of 9 nM brevetoxin-3 (PbTx-3) was close to equilibrium within 1 hr. The slow phase was not apparent when binding was done at 20 degrees C or when binding was done at 6 degrees C after the membrane sample had been preincubated at 4 degrees C for 1 day or at 22 degrees C for 1 hr. The 2-phase nature of association was not affected by substitution of KCl for choline chloride in the assay medium to produce sodium channel in the inactive state. Dissociation kinetics at 6 degrees C were also complex; the results fit well to a 2-phase curve with 55% of the dissociation in the rapid phase and t1/2 values of 13 and 64 min for the rapid and slow phases, respectively. The 2-phase nature did not change significantly after preincubation at 4 degrees C for 1 day. However, dissociation at 20 degrees C was rapid and fit a curve for 1-phase dissociation with a t1/2 of 2-6 min. At higher concentrations of PbTx-3, the binding is further complicated by the presence of 2-4 low-affinity binding sites with Kd values near 700 nM. In conclusion the association and dissociation of PbTx-3 with sodium channel from rat brain are complex processes that may involve changes in sodium channel conformation or interactions with other membrane (or membrane-associated) components.

Animals↗
PubMed1999

Use of a mechanical dissociation device to improve standardization of flow cytometric cytokeratin DNA measurements of colon carcinomas.

In order to standardize dual-fluorescence DNA flow cytometry using cytokeratin (CK) antibodies, normal colonic mucosa and tumor tissue were sampled from 308 colorectal surgical specimens. Fresh colon specimens were processed directly and stored frozen until dissociation. The samples were divided into aliquots for manual dissociation with tweezers and scalpel, and parallel dissociation with an automated disaggregation device (Medimachine, DAKO Diagnostika GmbH, Hamburg, Germany). An indirect immunofluorescence method with anti-cytokeratin antibodies and propidiumiodide was applied and measured on a single-laser flow cytometer (FACScan, Becton Dickinson [BDI], Heidelberg, Germany). Evaluation with CellFit (BDI) or MultiPlus (Phoenix Flow Systems, San Diego, CA) showed that dual-parameter fluorescence propidiumiodide (DNA staining) and fluorescein-isothiocyanate (cytokeratin labeling) provides a reasonable staining method for DNA analysis of epithelial cells. No significant differences in coefficient of variation in CK-gated versus ungated cells could be observed. Normal colon mucosa served as a reliable internal, diploid DNA control. Medimachine dissociation led to a significantly higher gain of cytokeratin-positive cells compared to percentage of cytokeratin-positive cells after manual tissue disaggregation. Cytokeratin gating led to a clear-cut separation of S-phase fractions within the respective ploidy groups, irrespective of manual or automated dissociation. The S-phase fraction increased significantly from normal tissue to diploid and nondiploid tumors. In general, automated tissue preparation with the Medimachine allows simple cell-isolation for dual DNA/CK-flow cytometric measurement, improving the gain of CK-positive cells, and facilitating a standardized DNA analysis.

Carcinoma↗
PubMed1995

Characterization of cancer cell dissociation factor in a highly invasive pancreatic cancer cell line.

BACKGROUND: Two pancreatic cancer cell lines, the highly invasive and metastatic cell line PC-1.0 and the weakly invasive and rarely metastatic cell line PC-1, were established from a pancreatic ductal carcinoma induced by N-nitrosobis (2-oxopropyl) amine in a Syrian golden hamster. METHODS: The cancer cell dissociation activity in serum-free conditioned medium of PC-1.0 cells was partially purified using a heparin column, a hydroxylapatite column, anion exchange, and gel filtration high-performance liquid chromatography. Several biologic properties of the partially purified activity were evaluated. RESULTS: Two cell lines exhibited different growth morphologic changes in vitro: the weakly invasive cell line PC-1 formed islandlike colonies, and the highly invasive cell line PC-1.0 grew mainly as single cells. The conditioned medium of PC-1.0 cells induced dissociation of islandlike colonies and morphologic changes of PC-1 cells to elongated cells, with a high frequency of pseudopodia formation similar to the morphologic findings of PC-1.0 cells. The dissociation activity did not bind to the heparin column and had an apparent molecular mass of > 400 kDa, as deduced from gel filtration. Several immunoreactive proteinous bands were observed in immunoblotting analysis using a polyclonal blocking antibody. The partially purified activity enhanced cell motility, chemoinvasion, and cell adhesion to plastic plates and fibronectin. CONCLUSIONS: Highly invasive and metastatic PC-1.0 cells produce a soluble proteinous factor, called "dissociation factor" (DF), which induces cell dissociation of weakly invasive and rarely metastatic PC-1 cells. It seems likely that DF has a role in tumor invasion and metastasis.

Adenocarcinoma↗
PubMed1994

Evidence of hemoglobin dissociation.

Bovine carbonmonoxy hemoglobin investigated with light scattering studies is found to dissociate from its native tetramer structure into dimers and monomers. The values of the hydrated tetramer radius, RT = 32.1 A, and the fractional dissociation vs pH, have been obtained at different ionic strengths from the autocorrelation function of the scattered light. The results suggest that a relevant contribution to Hb dissociation is due to electrostatic effects and, by means of a model derived by Tanford, it has been possible to predict the behavior of dissociation. Among the findings of this approach, we recall the estimates of the electrostatic energy contributions to Hb dissociation, up to congruent to 6RT, and the predicted charge of tetrameric Hb vs pH, which agrees very well with the experimental data.

Animals↗
PubMed2007

Development of thermodynamic models for simulating probe dissociation profiles in fluorescence in situ hybridization.

Stringency in ribosomal RNA (rRNA)-targeted fluorescence in situ hybridization (FISH) is typically adjusted with formamide, and the optimum formamide concentration at which the probe can hybridize with the target rRNA, but not with rRNAs with mismatches, is to be found experimentally. This is a difficult task when target or closest non-target organisms are not available in pure culture, or when there are numerous non-targets of concern. The objective of this work was to formulate mechanistic models capable of simulating the effect of formamide on probe dissociation. Using a previously described equilibrium model of FISH [Yilmaz and Noguera (2004) Applied and Environmental Microbiology 70(12):7126-7139] as the basis, the effect of formamide on free energy changes of probe-target duplex formation (DeltaG(1)(0)) and folding of target region (DeltaG(3)(0)) was simulated to be linear, and models differing in the definitions of the slopes of these relationships (m(1) and m(3)) were calibrated using experimental dissociation profiles for 27 probes targeting the 16S rRNA of Escherichia coli (E. coli). A good level of predictive power was obtained when m(1) was linearly related to probe length and when m(3) was made proportional to DeltaG(3)(0). The effect of single mismatches on probe dissociation with formamide was also studied, although at a preliminary level. The expected changes in DeltaG(1)(0) with the introduction of mismatches were not sufficient to capture the overall trends of mismatched dissociation profiles. In conclusion, this study offers the first theoretical method to calculate dissociation profiles for perfectly matched probes, and suggests a direction to systematically evaluate the effect of formamide on mismatched probes.

Base Pair Mismatch↗
PubMed2005

Influence of coadsorbates on the NO dissociation on a rhodium(311) surface.

Density functional theory (DFT) studies were performed to investigate the influence of coadsorbates on the nitrogen oxide dissociation on the vicinal rhodium(311) surface. This study amplifies prior studies on the dissociation of oxygen and nitrogen oxide on the (111) facet of rhodium. The influence of coadsorbates on the kinetic parameters and thermochemistry of the NO dissociation on Rh311 was studied. In addition, the activation energy and thermochemistry of this reaction were determined as a function of oxygen preoccupation/initial coverage. Steric and electronic effects and their influence on the dissociation reaction were examined. The results are discussed in the face of an NOx dissociation catalyst system proposed by Nakatsuji.

Journal Article↗
PubMed2006

Interaction of polyamine gene vectors with RNA leads to the dissociation of plasmid DNA-carrier complexes.

BACKGROUND: Plasmid DNA (pDNA) dissociation from polyamine gene vectors after cellular uptake has not been well characterized. A more detailed understanding of this process could lead to more efficient gene transfer agents. Since RNA is present in the cytoplasm at high concentrations and due to its structural similarity to DNA, we were interested in its conceivable interaction with polyamine gene vectors. METHODS: In a first set of experiments gene vectors were incubated in cell lysate and pDNA release was investigated by Southern blot analysis with or without RNase A pretreatment and by confocal laser scanning microscopy. Further, interaction of polyamine gene vectors with RNA was investigated by fluorescence quenching assay. These methods were complemented by a functionality assay using isolated nuclei. RESULTS: The incubation of gene vectors with cell lysate resulted in the dissociation of pDNA from the complexes. This effect was abolished when the cell lysate was pretreated with RNase A. The addition of RNA in the absence of cell lysate led also to a dissociation of pDNA. This process commenced instantaneously after the addition of RNA as analyzed by fluorescence quenching. When gene vectors were incubated in cell lysate containing isolated nuclei, the dissociation of pDNA from the polyamine gene vectors occurred preferentially extranuclearally as confirmed by confocal laser scanning microscopy. These results were further corroborated in a functional assay. CONCLUSIONS: These data suggest that RNA induces pDNA dissociation from the polyamine gene vectors. Furthermore, this process apparently occurs in the cytoplasm before the gene vectors enter the nucleus.

Cell Nucleus↗