Towards a cognitive model and measure of dissociation

Dissociation comprises a range of psychological processes, which have largely been the subject of psychodynamic discussion. Dissociative phenomena are for the most part unaddressed by cognitive theorists. Current measures are atheoretical and our understanding of dissociation has been hampered by the absence of clear psychological models. This paper describes a new cognitive model of dissociation and the development and validation of a theoretically based measure-the Wessex Dissociation Scale (WDS). The WDS has adequate internal consistency, shows convergent validity with the Dissociative Experiences Scale (DES-II), and is equivalent to the DES-II in its associations with severe psychopathology. However, the WDS has some advantages over the DES-II, in that it is sensitive to milder manifestations of dissociation, demonstrating links to less severe pathologies. The findings described here provide preliminary support for the usefulness of the cognitive model, and the varied consequences of dissociative processes. The clinical and research utility of the model and the scale are discussed.     

What we have learned about conducting randomized controlled trials in the NICHD MFMU network

The National Institute of Child Health and Human Development (NICHD) created the NICHD Maternal Fetal Medicine Units Network in 1986 to conduct randomized trials and observational studies in perinatal medicine to improve adverse pregnancy and infant outcomes. From 1986 to 2002, the Network has started 16 randomized trials. Five of the trials are described, with particular attention given to difficult issues that arose, such as feasibility, sample size estimation, randomization in very high risk pregnancies, changing clinical practice, importance of the study question to the investigators, and lack of recruitment. Changes that the Network group made to their organization and methodology as a result of these issues are described, together with their application to some of the other trials proposed and conducted by the group.     

Data monitoring and safety committees and their operations

The scientific burden of proof for new therapies and technologies in obstetrics and gynecology has risen steadily over the past 15 to 20 years, and the randomized clinical trial has become integral to this higher standard. Data monitoring and safety committees are now critical components of clinical trials, yet their history, rationale, methods of operation, and overall role have not been well-characterized in the obstetrics and gynecology literature. In this review, an overview of the important and evolving role of data monitoring and safety committees is provided. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader will be able to describe what a data monitoring and safety committee is, plan who should comprise the DMSC, and outline the functions of a DMSC.     

Identification of human serum interferants in the recombinant P-selectin glycoprotein ligand-1 clinical ELISA using MALDI MS and RP-HPLC

A colorimetric enzyme-linked immunosorbent assay (ELISA) was developed to detect circulating levels of rPSGL to permit pharmacokinetic analysis of clinical samples. The ELISA is an asymmetric sandwich utilizing a monoclonal antibody pair. Initial validation studies indicated that 57% of normal individuals scored above the limit of detection of the assay. Specificity experiments indicated that the signal was not due to circulating endogenous P-selectin glycoprotein ligand-1 (PSGL-1). Using matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) and sampling within the individual microplate wells, the interferant was detected in the vicinity of 6.6 kDa in lipemic and normal human sera, but not delipidized sera. These results were consistent with the ELISA data where 97.5% of known lipemic, 57% of normal, and 0% of delipidized sera scored above detectable limits in the ELISA. Preparative isolations of the 6.6 kDa species were performed using reversed-phase high performance liquid chromatography (RP-HPLC) with UV and MS detection. Edman N-terminal sequencing identified the 6.6 kDa unknown as Apolipoprotein C-I. Additional apolipoproteins were found by MALDI and RP-HPLC. Digestion of sera with liposome lipase and extraction of sera with anti-apolipoprotein C-I, C-II, and C-III antibody beads significantly reduced the ELISA interference. These experiments combined with the MALDI detection of phosphatidylcholine-type lipids from NHS eluate suggested that lipoprotein particles or remnants were causing the interference. A method combining Triton-X 100 with sonication was developed to overcome this interference without altering rPSGL recovery in the ELISA.     

Permeability of demineralized dentin to HEMA.

OBJECTIVES: The objectives of this study were to develop a macromodel of the demineralized layer of dentin that is formed after acid-etching, and to determine if the amount of HEMA uptake was responsive to air drying. The hypothesis that was tested was that HEMA uptake by demineralized dentin depends upon the degree of expansion of the collagen fibril network. METHODS: Dentin cubes (2 x 2 x 2 mm) were prepared in coronal dentin from extracted unerupted human third molars. They were incubated in 100% HEMA for up to 1000 min and then removed and blotted free of excess adherent HEMA. The HEMA taken up by each cube was extracted in 2 ml of water for 1 hr with shaking. This was repeated and the extracts combined. HEMA was quantitated spectrophometrically. The dentin cubes were then demineralized in 0.5 M EDTA for 10 days and the HEMA uptake remeasured at 1, 10, 100 and 1000 min. Then the cubes were air-dried and the HEMA uptake remeasured. After re-expanding the specimens in water, the cubes were stiffened in ascending concentrations of acetone of 100%, then allowed to air dry again in a more expanded state, and HEMA uptake was remeasured. Finally, after rehydration, the dentin cubes were "acid-etched" for 1 or 10 min with 37 wt% phosphoric acid and HEMA uptake remeasured. RESULTS: Before demineralization, the dentin took up little HEMA (ca. 4.8 x 10(-7) moles min-3) compared to after demineralization when the uptake for 10, 100 and 1000 min was 27.4, 43.8 and 51.4 x 10(-3) moles mm-3, respectively. Acid etching for 1 or 10 min had no effect on HEMA uptake. Air drying produced a 72% volumetric shrinkage but a 97% reduction in uptake. When the demineralized matrix was stiffened in acetone prior to air-drying, the volumetric shrinkage was only 27% and the HEMA uptake only fell 16% compared to the wet, fully expanded condition. SIGNIFICANCE: The results support the hypothesis that the uptake of HEMA by demineralized dentin depends on the degree of expansion of the dentin matrix.     

Ameloblastoma, calcifying epithelial odontogenic tumor, and glandular odontogenic cyst show a distinctive immunophenotype with some myoepithelial antigen expression

Background:  Odontogenic neoplasms have some morphologic overlap with salivary gland neoplasms, many of which show myoepithelial differentiation. In the 1980s, an ultrastructural study identified a population of myoepithelial-like cells in calcifying epithelial odontogenic tumor. Myoepithelial derived tumors have since been shown to have distinct immunohistochemical profiles.
Methods:  We examined a series of odontogenic neoplasms, including 11 ameloblastomas, four calcifying epithelial odontogenic tumors, five glandular odontogenic cysts (GOCs), and five keratocystic odontogenic tumors with a panel of myoepithelial-associated immunohistochemical stains. We also assessed representative control examples of oral mucosa, odontogenic rests, and dentigerous cysts.
Results:  All of the neoplastic and non-neoplastic oral epithelium-derived entities share a p63-positive, high molecular weight cytokeratin (CK5/6)-positive immunophenotype. Calponin reactivity was at least focally present in two of four calcifying epithelial odontogenic tumors, three of five GOCs, and 10 of 11 ameloblastomas; the sole completely non-reactive ameloblastoma represents a lung metastasis. One case of calcifying epithelial odontogenic tumor was focally positive for glial fibrillary acidic protein. However, other more definitive markers of myoepithelial differentiation, including S-100 and smooth muscle actin, were negative. Two of three calcifying epithelial odontogenic tumors and five of five GOCs were also positive for a low molecular weight cytokeratin (CK7).
Conclusions:  Ameloblastomas, GOCs, and calcifying epithelial odontogenic tumors show a distinctive immunophenotype which overlaps with that of myoepithelial-derived salivary gland neoplasms but does not provide definitive support for myoepithelial differentiation.     

Effects of fixed-appliance orthodontic treatment on DMF indices

An investigation was conducted to clarify the relationship between orthodontic treatment and caries incidence. DMF indices from 308 orthodontically treated and 305 untreated naval recruits were compared. Contrary to expectations, there was no evidence that orthodontic treatment increases caries experience. Orthodontically treated subjects had significantly fewer diseased surfaces--a difference averaging one less diseased surface per patient. Treatment status did not generally affect the number of filled surfaces. Treated subjects had more missing teeth if first premolars were considered, but untreated subjects had more missing teeth if first premolars were not considered. No significant correlation was found between caries incidence and duration of orthodontic treatment. The epidemiologic basis and significance of these findings are discussed.     

Study to examine the timeliness of care received by patients with open fractures of the lower limb.

The aim of this study was to identify deficiencies in the timeliness of emergency care received by patients with open fracture of the lower limb treated in the Accident and Emergency department at the City Hospital Truro, to help decide whether further investments in emergency ambulance services are warranted and, if so, where specific investments should be made. The ambulance service 'response time', 'on-scene times' and 'mission times', and the 'time to operation after attendance in casualty' were considered. The major deficiency in care identified was the long in-hospital delay before operation, probably resulting from unavailability of operating theatre staff. A lesser deficiency was that ambulance crew seemed to be spending too long on-scene. Suggestions are made on how to identify weaknesses in emergency service, and thus prevent costly and inappropriate investments.