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Publication
Journal: Oral surgery, oral medicine, and oral pathology
September/9/1982
Abstract
Direct immunofluorescent staining (DIF) was performed on biopsy specimens from thirty-five patients with oral lichen planus. The results showed fibrin deposition in all cases at the mucosal-submucosal interface, within colloid bodies (fourteen of thirty-five) and within vascular walls (five of thirty-five). Deposition of IgG, IgA and IgM was detected to a lesser extent, while complement (C3) could not be identified in any case. The significance of these findings was assessed by comparison with the IF results obtained in thirty-five biopsies from various oral diseases other than lichen planus and ten healty persons. Although the presence of fibrin deposition at the mucosal-submucosal junction, within vessels and cytoid bodies, was found to be highly characteristic of lichen planus, these findings were not specifically diagnostic. Morphologically identical deposits were also seen in lupus erythematosus. It is known at present whether immunologic reactions may play a role in the pathogenesis of lichen planus. However, the immunopathologic findings may occasionally be additional suggestive markers in the diagnosis of the disease.
Publication
Journal: Quality of Life Research
October/24/2007
Abstract
OBJECTIVE
To evaluate a modified version of the Roland-Morris Disability Questionnaire for differential item functioning (DIF) related to several covariates.
BACKGROUND
DIF occurs in an item when, after controlling for the underlying trait measured by the test, the probability of endorsing the item varies across groups.
METHODS
Secondary data analysis of two studies of participants with back pain (total n = 875). We used a hybrid item response theory/ logistic regression approach for detecting DIF. We obtained scores that accounted for DIF. We evaluated the impact of DIF on individual and group scores, and compared scores that ignored or accounted for DIF in terms of the strength of association with SF-36 subscale scores.
RESULTS
DIF was found in 18/23 items. Salient scale-level differential functioning was found related to age, education, and employment. Overall 24 participants (3%) had salient scale-level differential functioning. Mean scores across demographic groups differed minimally when accounting for DIF. The strength of association of scores with SF-36 scores was similar for scores that ignored and scores that accounted for DIF.
CONCLUSIONS
The modified version of the Roland-Morris Disability Questionnaire appears to have largely negligible DIF related to the covariates assessed here.
Publication
Journal: Indian Journal of Dermatology, Venereology and Leprology
April/24/2013
Abstract
Direct immunofluorescence (DIF) and indirect immunofluorescence (IIF) tests on skin biopsy are being done mostly in academic teaching hospitals. These tests provide a useful diagnostic aid to dermatologists. Immunohistology and serology can, in conjunction with histology, provide considerable help in delineation and diagnosis of various skin disorders as well as systemic diseases with skin involvement, e.g. systemic lupus erythematosus. Immunofluorescence (IF) studies have now become an invaluable supplement to clinical and histological examination in a variety of dermatological diseases. These skin diseases now include not only bullous and connective tissue disorders, vasculitides, and conditions such as lichen planus, but also the scaling dermatoses, notably psoriasis. In this review article, we share our experience of providing such a diagnostic facility for more than 30 years in a large tertiary care health center in North India and also help to outline the conditions, which can be diagnosed confidently, and others where IF can help in confirming a diagnosis or the immune component of the disease. The article also deals with handling of skin biopsy specimens and interpretation of biopsy findings on DIF and IIF examination.
Publication
Journal: Journal of Personality Assessment
March/12/1996
Abstract
The 20-item Toronto Alexithymia Scale (TAS-20) purportedly measures 3 intercorrelated dimensions of the alexithymia construct: (a) difficulties identifying feelings (DIF), (b) difficulties describing feelings (DDF), and (c) externally oriented thinking (EOT). The primary purpose of this study was to evaluate the factor structure of the TAS-20 with full-information item factor analysis in 2 diverse samples: medical students (n = 219) and psychiatric (psychoactive substance dependent-abusing) inpatients (n = 204). In each group, we estimated the parameters of 1-, 2-, 3-, and 4-factor models. None of the various factor solutions resulted in clean, simple structures in either sample. In the student sample, the data were best represented (although not well) by a 3-dimensional model: DIF, DDF, and EOT. In the psychiatric sample, however, the 3-dimensional solution was quite different; DIF and DDF formed 1 "emotional awareness deficits" factor, and EOT split into 2 unrelated factors. We concluded that alexithymia, as measured by the TAS-20, is multidimensional and not well-represented by a global severity score. Our recommendations include checking the factor structure of the TAS-20 when practicable, computing subscale scores, and exercising caution in interpreting TAS-20 EOT scores, particularly in psychoactive substance dependent-abusing inpatient samples.
Publication
Journal: Psychiatry and Clinical Neurosciences
July/29/2010
Abstract
OBJECTIVE
The purpose of the present study was to evaluate the prevalence of lifetime post-traumatic stress disorder (PTSD) in male alcohol-dependent inpatients and to investigate the relationship of PTSD with alexithymia and temperament and character dimensions.
METHODS
Participants were 156 consecutively admitted male alcohol-dependent subjects. Patients were investigated using the Clinician-Administered PTSD Scale (CAPS), the Toronto Alexithymia Scale (TAS-20) and the Temperament and Character Inventory (TCI).
RESULTS
Among alcohol-dependent inpatients 32.1% were considered as having lifetime PTSD. Mean scores of alexithymia, novelty seeking (NS), harm avoidance (HA) and self-transcendence (ST) were higher in the PTSD group, whereas age and self-directedness (S) were lower. Among age and other factors of TAS-20, 'difficulty in identifying feelings (DIF)' predicted PTSD in a logistic regression model. When age and personality dimensions of TCI were taken as independent variables, S predicted PTSD in the logistic regression model. Finally, among subscales of TCI, 'impulsiveness versus reflection' (NS2) and 'congruent second nature versus bad habits' (S5) predicted PTSD.
CONCLUSIONS
Alexithymia and personality traits, particularly high DIF and S scores are related with lifetime PTSD diagnosis, even when controlling for age among alcohol-dependent inpatients. Causal relationships between alexithymia, personality dimensions and PTSD, and their implications on treatment are not clear and should be evaluated in longitudinal studies.
Publication
Journal: Indian Journal of Community Medicine
April/2/2014
Abstract
BACKGROUND
Multiple choice questions (MCQs) are frequently used to assess students in different educational streams for their objectivity and wide reach of coverage in less time. However, the MCQs to be used must be of quality which depends upon its difficulty index (DIF I), discrimination index (DI) and distracter efficiency (DE).
OBJECTIVE
To evaluate MCQs or items and develop a pool of valid items by assessing with DIF I, DI and DE and also to revise/ store or discard items based on obtained results.
METHODS
Study was conducted in a medical school of Ahmedabad.
METHODS
An internal examination in Community Medicine was conducted after 40 hours teaching during 1(st) MBBS which was attended by 148 out of 150 students. Total 50 MCQs or items and 150 distractors were analyzed.
METHODS
Data was entered and analyzed in MS Excel 2007 and simple proportions, mean, standard deviations, coefficient of variation were calculated and unpaired t test was applied.
RESULTS
Out of 50 items, 24 had "good to excellent" DIF I (31 - 60%) and 15 had "good to excellent" DI >> 0.25). Mean DE was 88.6% considered as ideal/ acceptable and non functional distractors (NFD) were only 11.4%. Mean DI was 0.14. Poor DI (< 0.15) with negative DI in 10 items indicates poor preparedness of students and some issues with framing of at least some of the MCQs. Increased proportion of NFDs (incorrect alternatives selected by < 5% students) in an item decrease DE and makes it easier. There were 15 items with 17 NFDs, while rest items did not have any NFD with mean DE of 100%.
CONCLUSIONS
Study emphasizes the selection of quality MCQs which truly assess the knowledge and are able to differentiate the students of different abilities in correct manner.
Publication
Journal: Behavior Genetics
July/20/2004
Abstract
Variation in intake of sweet and bitter solutions by inbred strains of laboratory mice has helped identify genes related to taste behaviors; but similar information is not available for golden hamsters (Mesocricetus auratus ), a species used much in taste research. Thus, 6-hour, 1-bottle intake by water-replete hamsters of 7 inbred strains was measured for water and 2 concentrations of sucrose, maltose, D-phenylalanine (D-Phe), and sodium saccharin, which are sweet; and quinine.HCl, L-phenylalanine (L-Phe), caffeine, and sucrose octaacetate (SOA), which are bitter to humans. Difference scores (DIF), calculated as solution intake minus mean baseline water intake (mL) for each animal, were evaluated by analysis of variance. Compared to ACN, CN, APA, APG, and CBN, five strains with similar DIF for all compounds, GN, an ancestral strain of ACNT, and ACNT preferred sucrose, caffeine, and SOA more strongly; ACNT also preferred saccharin and maltose more strongly and rejected quinine more strongly. Narrow sense heritabilities for the 6 compounds for which strain differences were revealed ranged from 0.31 to 0.57. Genetic correlations indicated the strain variations in intake of sucrose, saccharin, SOA, and caffeine were coupled; a statistical association with several possible interpretations. Intakes of the two amino acids, preferred D-Phe and aversive L-Phe, did not reveal strain differences, and heritability ranged from 0.13 to 0.23 for the two optical isomers. Thus, although, compared to mice, genetic variation in laboratory hamsters may be small, genetic differences that influence taste behaviors in existing strains may help identify relevant genes.
Publication
Journal: Global journal of health science
November/12/2013
Abstract
Limited studies have examined the effect of differential item functioning (DIF) on comparing health related quality of life (HRQoL) scores across child self-reports and parent proxy-reports. This study aims to determine whether parents and children respond differently to the items in the Persian version of the PedsQoLTM 4.0 measure. The PedsQLTM 4.0 Generic Core Scales was completed by 938 child-parent dyads. The graded response model (GRM) was used to detect DIF between parents and children. The IRT analyses were conducted using IRTPRO 2.1.On the whole, our findings showed that 50% (4 out of 8) of the items in the physical subscale and 40% (2 out of 5) in both emotional and school subscales were flagged with DIF. Among the DIF items, 62.5% (5 out of 8) were uniform and the remaining 37.5% (3 out of 8) were non-uniform. Parents and children interpret certain items of the PedsQLTM 4.0 in a different ways, except for the social subscale. Hence, we should be cautious about using parent proxy-report as a substitute for a child's ratings.
Publication
Journal: Journal of Sex and Marital Therapy
March/12/2008
Abstract
This article reports the findings of a study investigating alexithymia, emotional instability, and vulnerability to stress proneness among individuals (N = 120) seeking help for hypersexual behavior. At the onset of treatment at an outpatient community clinic, subjects completed the Sexual Compulsivity Scale (SCS), the 20-item Toronto Alexithymia Scale (TAS-20), and the NEO Personality Inventory Revised (NEO-PI-R). The results of a hierarchical regression analysis revealed the best model in predicting severity of hypersexual behavior included the facets of depression and vulnerability to stress from the NEO and the Difficulty Identifying Feelings (DIF) factor of the TAS-20. Although the NEO domain of neuroticism appeared to capture the majority of variance in hypersexual behavior, the difficulty identifying feelings factor of the TAS-20 did make some modest, but significant, contribution to the severity of hypersexual behavior after controlling for depression and vulnerability to stress. These data provide evidence for the hypothesis that individuals who manifest symptoms of hypersexual behavior are more likely to experience deficits in affect regulation and negative affect (including alexithymia, depression, and vulnerability to stress). Possible reasons for these results are suggested and future recommendations for research are offered.
Publication
Journal: Journal of the American Academy of Dermatology
January/29/2009
Abstract
BACKGROUND
Direct immunofluorescent (DIF) testing defines an important diagnostic adjunct in the classification of various inflammatory skin conditions; it requires fresh tissue, a laboratory equipped to perform the procedure, and a pathologist skilled in its interpretation. Although advances have been made in the development of antibodies that can be applied to paraffin-embedded tissue, there has been no reported success on the application of paraffin tissue-based immunohistochemistry as a potential substitute for DIF testing on skin biopsy material.
OBJECTIVE
We applied C3d and C4d immunohistochemistry on paraffin-embedded, formalin-fixed tissue to define a potential application of these two antibodies as a diagnostic adjunct in the evaluation of various inflammatory skin diseases.
METHODS
A natural language search identified cases submitted for both light microscopic and DIF studies from July 2006 to August 2007. We prospectively included similar cases encountered from August 2007 to March 2008. We correlated the C3d and C4d staining pattern with the DIF and light microscopic findings.
RESULTS
All cases of scarring discoid lupus erythematosus (LE) (20/20) and systemic LE (5/5) showed prominent granular C3d along the dermoepidermal junction (DEJ) and a positive lupus band test result in the latter by DIF. All systemic LE cases demonstrated granular DEJ C4d with C3d or C4d in blood vessels (BV). There was a negative lupus band test result without DEJ C3d or C4d in all cases of subacute cutaneous lupus erythematosus (SCLE) (15/15). There were, however, deposits of C4d within epidermal keratinocytes (7/7), corresponding to IgG decoration of keratinocytes by DIF and the presence of anti-Ro antibodies. Dermatomyositis cases showed prominent mural C3d and C4d in BV corresponding to C5b-9 by DIF (12/12) and one case of hydroxyurea-induced dermatomyositis lacked this staining. Although by DIF all dermatomyositis cases had a negative lupus band test result, 25% of cases showed staining for C3d along the DEJ (3/9). Bullous pemphigoid cases demonstrated homogenous DEJ C3d (17/17) whereas C4d was characteristically negative; there was 100% concordance with linear IgG and C3d by DIF. Eighty two percent of pemphigus cases demonstrated prominent intercellular C3d and C4d, roughly mirroring the intercellular pattern for IgG and complement seen by DIF (9/11). Porphyria cases showed homogeneous and granular C3d (11/11) and C4d (7/11), mirroring the vascular immunoglobulin and C5b-9 by DIF. All cases of urticarial (5), leukocytoclastic (6), and lymphocytic (1) vasculitis exhibited prominent mural C3d and C4d in BV, whereas Henoch-Schönlein purpura (10/10) showed primarily mural BV C3d without C4d, with IgA by DIF. Three cases of relapsing polychondritis showed C3d and C4d within chondrocyte nuclei (3/3), in contrast to negative staining in chondrodermatitis nodularis helicis (0/2). Hypersensitivity reactions were negative for C3d and C4d.
CONCLUSIONS
The small sample size in each category is a limitation. The lack of literature precedent with regard to immunohistochemical assessment of extracellular antigens on paraffin-embedded tissue in skin samples is another limitation of this study.
CONCLUSIONS
When correlated with the light microscopic and clinical findings, the C3d and C4d assay has significant application in the assessment of select inflammatory skin diseases including vasculopathic conditions, collagen vascular disease, and autoimmune vesiculobullous disorder. It may prompt further DIF testing or, in some instances, may even define a reasonable substitute for DIF and/or add to the morphologic assessment of a biopsy specimen submitted for routine light microscopic assessment primarily in the setting of autoimmune vesiculobullous disease and collagen vascular disease.
Publication
Journal: Psychological test and assessment modeling
July/17/2017
Abstract
Measures of magnitude and impact of differential item functioning (DIF) at the item and scale level, respectively are presented and reviewed in this paper. Most measures are based on item response theory models. Magnitude refers to item level effect sizes, whereas impact refers to differences between groups at the scale score level. Reviewed are magnitude measures based on group differences in the expected item scores and impact measures based on differences in the expected scale scores. The similarities among these indices are demonstrated. Various software packages are described that provide magnitude and impact measures, and new software presented that computes all of the available statistics conveniently in one program with explanations of their relationships to one another.
Publication
Journal: Analytical Chemistry
May/24/2000
Abstract
Velocity-difference induced focusing (V-DIF) of nucleotides was achieved by using a dynamic pH junction in capillary electrophoresis (CE) with UV detection. The influence of specific analyte properties, such as nucleotide base structure, sugar structure, and degree of phosphorylation, is examined. The pKa values and borate complexation with vicinal diols are important factors that caused the focusing. Therefore, the pH and borate content in the sample and background electrolyte can be adjusted to optimize the focusing effect. This method allows the injection of large volumes of sample (approximately 300 nL), resulting in at least 50-fold improvement in concentration sensitivity. The detection limit of 4.0 x 10(-8) M for nucleotides can be achieved in favorable conditions. V-DIF can be also applied to nucleotide pool analysis from cell extracts to improve the concentration sensitivity of CE and to reduce the time-consuming steps of desalting and off-line preconcentration that are often required for assays of nucleotides from biological samples.
Publication
Journal: PLoS ONE
April/7/2014
Abstract
Differentiation-inducing factor-3 (DIF-3), found in the cellular slime mold Dictyostelium discoideum, and its derivatives such as butoxy-DIF-3 (Bu-DIF-3) are potent anti-tumor agents. However, the precise mechanisms underlying the actions of DIF-3 remain to be elucidated. In this study, we synthesized a green fluorescent derivative of DIF-3, BODIPY-DIF-3, and a control fluorescent compound, Bu-BODIPY (butyl-BODIPY), and investigated how DIF-like molecules behave in human cervical cancer HeLa cells by using both fluorescence and electron microscopy. BODIPY-DIF-3 at 5-20 µ M suppressed cell growth in a dose-dependent manner, whereas Bu-BODIPY had minimal effect on cell growth. When cells were incubated with BODIPY-DIF-3 at 20 µM, it penetrated cell membranes within 0.5 h and localized mainly in mitochondria, while Bu-BODIPY did not stain the cells. Exposure of cells for 1-3 days to DIF-3, Bu-DIF-3, BODIPY-DIF-3, or CCCP (a mitochondrial uncoupler) induced substantial mitochondrial swelling, suppressing cell growth. When added to isolated mitochondria, DIF-3, Bu-DIF-3, and BOIDPY-DIF-3, like CCCP, dose-dependently promoted the rate of oxygen consumption, but Bu-BODIPY did not. Our results suggest that these bioactive DIF-like molecules suppress cell growth, at least in part, by disturbing mitochondrial activity. This is the first report showing the cellular localization and behavior of DIF-like molecules in mammalian tumor cells.
Publication
Journal: Clinical Therapeutics
February/17/2010
Abstract
BACKGROUND
Drug-drug interactions (DDIs) can lead to adverse clinical outcomes, particularly in oncology, because of the narrow therapeutic index of chemotherapeutic agents and because patients with cancer are at a high risk due to polypharmacy and age-related organ dysfunction. In a previously published study, drug profiles were developed based on primary and tertiary literature reviews for a list of clinically significant DDIs involving 28 oral anticancer agents (OAAs).
OBJECTIVE
This study was based on a Delphi survey of oncology pharmacists; the survey results were used to develop a consensus list of clinically significant DDIs involving OAAs and nonanticancer agents.
METHODS
In this study, the DDI profiles previously developed were updated, and the DDI pairs that were listed both in the 2009 Drug Interaction Facts (DIF) and the Thomson Micromedex DrugDex System compendia and that also met the predetermined criteria for clinical significance were selected for further evaluation. In a 2-round, electronically administered Delphi survey of oncology pharmacists, a 5-point Likert scale (1-5, where 1 = strongly agree and 5 = strongly disagree) was used to evaluate the DDI pairs based on 8 clinical aspects (clinical importance; irreversible morbidity and mortality; quality of data; quantity of data; patient's organ functions; comorbid conditions; awareness of interaction; and management burden). International pharmacists who specialized in oncology pharmacy practice and had>> or =5 years of practice experience were eligible to participate.
RESULTS
Nine of the 23 surveyed pharmacists responded, giving a response rate of 39.1%. A total of 37 DDI pairs were selected from DIF and DrugDex and evaluated by the survey respondents, resulting in the identification, via consensus, of 12 clinically significant DDI pairs. The clinical aspects with the most DDIs that reached consensus of agreement were clinical importance (82.9%) and awareness of interaction (73.2%).
CONCLUSIONS
An expert panel identified 12 clinically significant DDIs involving OAAs.
Publication
Journal: Quality of Life Research
September/11/2014
Abstract
OBJECTIVE
The objective of the present study is to describe the extension of the National Institutes of Health Patient-Reported Outcomes Measurement Information System (PROMIS(®)) pediatric parent proxy-report item banks for parents of children ages 5-7 years, and to investigate differential item functioning (DIF) between the data obtained from parents of 5-7-year-old children with the data obtained from parents of 8-17 year-old children in the original construction of the scales.
METHODS
Item response theory (IRT) analyses of DIF were conducted comparing data from the 5-7 age group with data from the established scales for ages 8-17 across 5 generic health domains (physical functioning, pain, fatigue, emotional health, and social health) and asthma.
RESULTS
IRT DIF analyses revealed that the majority of the items functioned similarly with responses from parents of younger and older children. A small number of items were removed from the item bank for younger children, and a few items that exhibited statistical DIF were retained in the pools with the caveat that they should not be used in studies that involve comparisons of younger children with older children.
CONCLUSIONS
The study confirms that most of the items in the PROMIS parent proxy-report item banks can be used with parents of children ages 5-7. It is anticipated that these new scales will have application for younger pediatric populations when pediatric self-report is not feasible.
Publication
Journal: Development Growth and Differentiation
June/21/2007
Abstract
Differentiation-inducing factors (DIFs) are required for stalk cell formation in Dictyostelium discoideum. In the present study, in order to support our hypothesis that DIFs may function via increases in [Ca(2+)](c) and [H(+)](c), we investigated the combined effects of 5,5-dimethyl-2,4-oxazolidinedione (DMO, a [H(+)](c)-increasing agent), thapsigargin (Tg) and BHQ ([Ca(2+)](c)-increasing agents) on in vitro stalk cell formation in several strains. DMO, in combination with Tg or BHQ, induced stalk cell formation in a DIF-deficient mutant HM44. Although the rates of stalk cell induction by the drugs were low in the presence of cerulenin (an inhibitor of endogenous DIF production) in HM44 and V12M2 (a wild-type strain), the drugs succeeded in inducing sufficient stalk cell formation when a small amount of DIF-1 was supplied. Furthermore, co-addition of DMO, BHQ and a small amount of DIF-1 also induced sufficient stalk cell formation in AX-4 (an axenic strain) and HM1030 (dmtA(-)) but not in CT15 (dimA(-)). The drugs suppressed spore formation and promoted stalk cell formation in both HM18 (a sporogenous mutant) and 8-bromo-cAMP-stimulated V12M2. The present results suggest that DIFs function, at least in part, via increases in [Ca(2+)](c) and [H(+)](c) in D. discoideum.
Publication
Journal: BMC Medical Research Methodology
January/17/2012
Abstract
BACKGROUND
For the Low Vision Quality Of Life questionnaire (LVQOL) it is unknown whether the psychometric properties are satisfactory when an item response theory (IRT) perspective is considered. This study evaluates some essential psychometric properties of the LVQOL questionnaire in an IRT model, and investigates differential item functioning (DIF).
METHODS
Cross-sectional data were used from an observational study among visually-impaired patients (n = 296). Calibration was performed for every dimension of the LVQOL in the graded response model. Item goodness-of-fit was assessed with the S-X(2)-test. DIF was assessed on relevant background variables (i.e. age, gender, visual acuity, eye condition, rehabilitation type and administration type) with likelihood-ratio tests for DIF. The magnitude of DIF was interpreted by assessing the largest difference in expected scores between subgroups. Measurement precision was assessed by presenting test information curves; reliability with the index of subject separation.
RESULTS
All items of the LVQOL dimensions fitted the model. There was significant DIF on several items. For two items the maximum difference between expected scores exceeded one point, and DIF was found on multiple relevant background variables. Item 1 'Vision in general' from the "Adjustment" dimension and item 24 'Using tools' from the "Reading and fine work" dimension were removed. Test information was highest for the "Reading and fine work" dimension. Indices for subject separation ranged from 0.83 to 0.94.
CONCLUSIONS
The items of the LVQOL showed satisfactory item fit to the graded response model; however, two items were removed because of DIF. The adapted LVQOL with 21 items is DIF-free and therefore seems highly appropriate for use in heterogeneous populations of visually impaired patients.
Publication
Journal: Journal of Aging and Health
October/17/2012
Abstract
OBJECTIVE
Measure modification can impact comparability of scores across groups and settings. Changes in items can affect the percent admitting to a symptom.
METHODS
Using item response theory (IRT) methods, well-calibrated items can be used interchangeably, and the exact same item does not have to be administered to each respondent, theoretically permitting wider latitude in terms of modification.
RESULTS
Recommendations regarding modifications vary, depending on the use of the measure. In the context of research, adjustments can be made at the analytic level by freeing and fixing parameters based on findings of differential item functioning (DIF). The consequences of DIF for clinical decision making depend on whether or not the patient's performance level approaches the scale decision cutpoint. High-stakes testing may require item removal or separate calibrations to ensure accurate assessment.
CONCLUSIONS
Guidelines for modification based on DIF analyses and illustrations of the impact of adjustments are presented.
Publication
Journal: Health and Quality of Life Outcomes
February/12/2013
Abstract
BACKGROUND
The study aimed at presenting normative data for both parallel forms of the "Rasch-based Depression Screening (DESC)", to examine its Rasch model conformity and convergent and divergent validity based on a representative sample of the German general population.
METHODS
The sample was selected with the assistance of a demographic consulting company applying a face to face interview (N = 2509; mean age = 49.4, SD = 18.2; 55.8% women). Adherence to Rasch model assumptions was determined with analysis of Rasch model fit (infit and outfit), unidimensionality, local independence (principal component factor analysis of the residuals, PCFAR) and differential item functioning (DIF) with regard to participants' age and gender. Norm values were calculated. Convergent and divergent validity was determined through intercorrelations with the depression and anxiety subscales of the Hospital Anxiety and Depression Scale (HADS-D and HADS-A).
RESULTS
Fit statistics were below critical values (< 1.3). There were no signs of DIF. The PCFAR revealed that the Rasch dimension "depression" explained 68.5% (DESC-I) and 69.3% (DESC-II) of the variance, respectively which suggests unidimensionality and local independence of the DESC. Correlations with HADS-D were rDESC-I = .61 and rDESC-II = .60, whereas correlations with HADS-A were rDESC-I = .62 and rDESC-II = .60.
CONCLUSIONS
This study provided further support for the psychometric quality of the DESC. Both forms of the DESC adhered to Rasch model assumptions and showed intercorrelations with HADS subscales that are in line with the literature. The presented normative data offer important advancements for the interpretation of the questionnaire scores and enhance its usefulness for clinical and research applications.
Publication
Journal: Human Brain Mapping
July/12/2015
Abstract
Alexithymia is perceived as a personality construct involving deficits in the cognitive processing of emotion. Brain areas that process emotions might be structurally altered in affected people. Subjects from the Study of Health in Pomerania who underwent whole body magnetic resonance imaging were investigated. After quality control procedures 2,589 subjects with Toronto Alexithymia Scale 20 (TAS-20) data and interview-based information on major depressive disorder (MDD) were available. After exclusion of study participants who were older than 65 years or had MDD in their lifetime, 1,685 subjects were included in the voxel-based morphometric (VBM 8) analyses. In whole-brain analyses, the TAS-20 total score was associated with less gray matter (GM) volumes of the bilateral dorsal anterior cingulate cortex (dACC). The TAS-20 factor scale difficulty identifying feelings (DIF) was associated with less GM volume in three clusters: dACC, left middle and inferior temporal gyrus, left fusiform gyrus and cerebellum. The lower GM volume in the left fusiform gyrus was specific for females. Absolute GM volume analyses also revealed associations between the factor scales difficulty describing feelings, external orientated thinking and the dACC. Adjustment for current symptoms of anxiety and depression did not change the effects sizes substantially. In conclusion, lower GM volume in the dACC represents the major structural correlate of alexithymia. Associations with DIF suggest a prominent involvement of left temporal areas. These areas represent language and semantic processing and might be involved in the cognitive processing of emotions and the conscious identification of feelings.
Publication
Journal: Disability and Rehabilitation
January/21/2008
Abstract
OBJECTIVE
To evaluate the cross-cultural validity of the five subscales of the Impact on Participation and Autonomy (IPA) measure and the full 31-item scale.
METHODS
Data from two validation studies (Dutch and English) were pooled (n = 106). Participants (aged 18-75), known to rehabilitation services or GP practices, had conditions ranging from minor ailments to significant disability. Validity of the five subscales and the total scale was examined using Rasch analysis (Partial Credit Model). P values smaller than 0.01 were employed to allow for multiple testing.
RESULTS
A number of items in all the subscales except 'Outdoor Autonomy' needed rescoring. One 'Indoor Autonomy' item showed uniform DIF by country and was split by country. One 'Work and Education' item displayed uniform and non-uniform DIF by gender. All the subscales fitted the Rasch model and were invariant across country. A 30-item IPA also fitted the Rasch model.
CONCLUSIONS
The IPA subscales and a 30-item scale are invariant across the two cultures and gender. The IPA can be used validly to assess participation and autonomy in these populations. Further analyses are required to examine whether the IPA is invariant across differing levels of disability and other disease groups not included in this study.
Publication
Journal: Archives of Dermatological Research
March/11/2010
Abstract
Examining the patients with a new variant of endemic pemphigus foliaceus (EPF) in El Bagre, Colombia, (El Bagre-EPF), we noted several polymorphic clinical lesions around their axillary areas. Based on our clinical findings and on previous histopathological studies on the skin of these patients that showed abnormalities in their sweat glands, and the presence of mercuric selenides and iodines by autometallography assay, we decided to investigate immunoreactivity to the sweat glands in these patients. We tested for autoreactivity utilizing direct and indirect immunofluorescence (DIF, IIF). To be able to distinguish between non-specific immune deposits and real autoimmune response, and knowing that sweat glands have some intrinsic autofluorescence for the presence of lipofuscin granules (that naturally fluoresce under the UV light microscope), as well as by the presence of secretory IgA, we used simultaneously immunohistochemistry (IHC). We tested ten El Bagre-EPF patients, ten healthy controls from the endemic area and ten healthy controls from the United States. We were able to visualize a specific autoreactivity to sweat glands in 8/10 cases of El Bagre-EPF by DIF, IIF and by IHC. In addition when using anti-human monoclonal antibodies to CD3, CD68, and CD20, we confirmed the presence of several specific immune responses in situ, an around the sweat glands. No healthy control cases yielded positive findings. In some chronic cases, decrease and sometimes a complete absence of sweat glands and other skin appendices was found. In addition to this, sclerodermoid changes or early sclerodermatous changes sometimes extending into the adipose tissue as a membranous lipodystrophy were observed. Autoreactivity to the neurovascular components around the sweat glands were also observed. Our data demonstrate for the first time that there is immunoreactivity toward sweat glands in El Bagre-EPF patients that seems to destroy some of these structures.
Publication
Journal: Gastroenterology
April/12/2019
Abstract
The mechanisms of hepatitis C virus (HCV) infection, liver disease progression, and hepatocarcinogenesis are only partially understood. We performed genomic, proteomic, and metabolomic analyses of HCV-infected cells and chimeric mice to learn more about these processes.

METHODS
Huh7.5.1dif (hepatocyte-like cells) were infected with culture-derived HCV and used in RNA sequencing, proteomic, metabolomic, and integrative genomic analyses. uPA/SCID (urokinase-type plasminogen activator/severe combined immunodeficiency) mice were injected with serum from HCV-infected patients; 8 weeks later, liver tissues were collected and analyzed by RNA sequencing and proteomics. Using differential expression, gene set enrichment analyses, and protein interaction mapping, we identified pathways that changed in response to HCV infection. We validated our findings in studies of liver tissues from 216 patients with HCV infection and early-stage cirrhosis and paired biopsy specimens from 99 patients with hepatocellular carcinoma, including 17 patients with histologic features of steatohepatitis. Cirrhotic liver tissues from patients with HCV infection were classified into 2 groups based on relative peroxisome function; outcomes assessed included Child-Pugh class, development of hepatocellular carcinoma, survival, and steatohepatitis. Hepatocellular carcinomas were classified according to steatohepatitis; the outcome was relative peroxisomal function.

We quantified 21,950 messenger RNAs (mRNAs) and 8297 proteins in HCV-infected cells. Upon HCV infection of hepatocyte-like cells and chimeric mice, we observed significant changes in levels of mRNAs and proteins involved in metabolism and hepatocarcinogenesis. HCV infection of hepatocyte-like cells significantly increased levels of the mRNAs, but not proteins, that regulate the innate immune response; we believe this was due to the inhibition of translation in these cells. HCV infection of hepatocyte-like cells increased glucose consumption and metabolism and the STAT3 signaling pathway and reduced peroxisome function. Peroxisomes mediate β-oxidation of very long-chain fatty acids; we found intracellular accumulation of very long-chain fatty acids in HCV-infected cells, which is also observed in patients with fatty liver disease. Cells in livers from HCV-infected mice had significant reductions in levels of the mRNAs and proteins associated with peroxisome function, indicating perturbation of peroxisomes. We found that defects in peroxisome function were associated with outcomes and features of HCV-associated cirrhosis, fatty liver disease, and hepatocellular carcinoma in patients.We performed combined transcriptome, proteome, and metabolome analyses of liver tissues from HCV-infected hepatocyte-like cells and HCV-infected mice. We found that HCV infection increases glucose metabolism and the STAT3 signaling pathway and thereby reduces peroxisome function; alterations in the expression levels of peroxisome genes were associated with outcomes of patients with liver diseases. These findings provide insights into liver disease pathogenesis and might be used to identify new therapeutic targets.
Publication
Journal: Journal of the European Academy of Dermatology and Venereology
April/11/2002
Abstract
BACKGROUND
The epidemiology of bullous pemphigoid (BP) is not clear because of the heterogeneity of the disease, and its possible association with internal malignancies has been under debate for many years. We report the findings of a 2-year study on incident BP cases in the Liguria region of Italy.
METHODS
Thirty-two patients with BP were collected over the 2-year period. Diagnosis was made based on clinical findings and confirmed by histology, direct immunofluorescence (DIF) and indirect immunofluorescence (IIF) with salt-split skin and monkey oesophagus, and immunoblotting (IB). All patients were thoroughly investigated for possible malignancies and all were followed up for 6 months to monitor the response to treatment.
RESULTS
DIF showed linear deposits at the dermoepidermal junction in all but one patient. IIF gave positive findings for 15 sera tested with monkey oesophagus and 20 tested with salt-split skin. IB gave positive findings in 19 cases. There was a malignancy in six cases, but no clinical or immunological features that could be considered to predict this occurrence.
CONCLUSIONS
The findings of this study are in accordance with most of the data found in the literature, including the fact that IgG serum levels did not predict the course of the disease. Contrary to previous indications, IgE levels were not indicative of disease course either. Mucosal lesions, erythema multiform-like lesions, negative IIF findings and antibodies to AgPB2 were not a prediction for the development of malignancy.
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