OBJECTIVE

The aim of this study was to use Item Response Theory to assess Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised (DSM-III-R), lifetime cannabis-use disorder (CUD) symptom severity and its relationship to first cannabis use before age 15 years, male gender, and childhood conduct disorder in an American Indian community sample.

METHODS

The Semi-Structured Assessment for the Genetics of Alcoholism was used to determine demographic information, age at first use, and DSM-III-R childhood conduct disorder and lifetime CUD symptoms in a community sample of 349 American Indian participants who had used cannabis at least 21 times in a single year. Two-parameter Item Response Theory models generated marginal maximum likelihood estimates for discrimination (a) and threshold (b) parameters for nine DSM-III-R CUD symptoms along an underlying latent CUD severity continuum. Differential Item Functioning (DIF) analysis was used to assess for differences in symptom severity in groups defined by presence versus absence of age at first use before 15 years, male gender, and childhood conduct disorder.

RESULTS

CUD symptoms of "use in larger amounts or over longer periods of time," "activities given up," and "role failure" were the most severe symptoms. All CUD symptoms fell on the moderate portion of the severity continuum. "Time spent" was more severe in individuals who first used cannabis after age 15 years, "hazardous use" was more severe in females, and "use in larger amounts or over longer periods of time" was more severe in individuals with co-morbid childhood conduct disorder.

CONCLUSIONS

Specific risk factors for the development of lifetime CUD are associated with increased severity of several CUD symptoms in this high-risk group.

OBJECTIVE

Sleep is known to increase as an acute response to infection. However, the function of this behavioral response in host defense is not well understood. To address this problem, we evaluated the effect of acute sleep deprivation on post-infection sleep and immune function in Drosophila.

METHODS

Laboratory.

METHODS

Drosophila melanogaster.

RESULTS

Flies were subjected to sleep deprivation before (early DEP) or after (late DEP) bacterial infection. Relative to a non-deprived control, flies subjected to early DEP had enhanced sleep after infection as well as increased bacterial clearance and survival outcome. Flies subjected to late DEP experienced enhanced sleep following the deprivation period, and showed a modest improvement in survival outcome. Continuous DEP (early and late DEP) throughout infection also enhanced sleep later during infection and improved survival. However, improved survival in flies subjected to late or continuous DEP did not occur until after flies had experienced sleep. During infection, both early and late DEP enhanced NFκB transcriptional activity as measured by a luciferase reporter (κB-luc) in living flies. Early DEP also increased NFκB activity prior to infection. Flies that were deficient in expression of either the Relish or Dif NFκB transcription factors showed normal responses to early DEP. However, the effect of early DEP on post-infection sleep and survival was abolished in double mutants, which indicates that Relish and Dif have redundant roles in this process.

CONCLUSIONS

Acute sleep deprivation elevated NFκB-dependent activity, increased post-infection sleep, and improved survival during bacterial infection.

Different regions of RF DNA from the filamentous bacteriophage phiLf were cloned in Escherichia coli vectors that can not be maintained in Xanthomonas. After introduction into X. campestris pv. campestris 17 (Xc17), most of these constructs were found to integrate into the host chromosome, either by recA-dependent homologous recombination or recA-independent site-specific integration. Mutations in himA, which codes for the alpha-subunit of the Integration Host Factor, does not affect the integration. Integration occurs into a chromosomal region which harbors a copy of a defective phage (4445 bp) that shares a high degree of identity with the phiLf genome. While various parts of the 4445-bp region are susceptible to homologous recombination, site-specific integration requires the attB sequence on the chromosome and the phage attP. The attB shows a high level of sequence identity (22 out of 28 bp) to the dif site required for E. coli Xer site-specific recombination, including the 6-bp central region, and 8/11 identity in both the left XerC-binding arm and the right XerD-binding arm, with the innermost 5 nt of the arms forming a dyad symmetry that is also present in dif. The attP has the same central region and shows 10/11 identity to the dif site in the left arm, but the sequence of the right arm is less conserved than that of attB. The smallest regions still capable of mediating integration are a cloned 72-bp phiLf attP-containing sequence and a 51-bp Xc17 attB-containing sequence, which was reinserted into the Xc17 chromosome after the 4445-bp region had been deleted, indicating that accessory sequences are not necessary and that the integrase required for site-specific integration is neither specified by the 4445-bp Xc17 chromosomal region nor encoded by the phiLf genome.

Differentiation-inducing factor-1 (DIF-1) is a putative morphogen that induces stalk cell formation in the cellular slime mold Dictyostelium discoideum. In this study, we have examined the effects of DIF-1 on the human leukemia HL-60 cells. DIF-1 at 10-40 microM suppressed cell growth in a dose-dependent manner, and approximately 50% growth inhibition was attained with 15-20 microM DIF-1. FACS analysis of cell-cycle phase distribution using propidium iodide revealed that many cells were accumulated in the G1 phase after treatment with 15-20 microM DIF-1. These concentrations of DIF-1 also raised [Ca2+]i in a dose-dependent manner irrespective of the presence of extracellular Ca2+, indicating that DIF-1 elicited Ca2+-release from some intracellular Ca2+ store(s). Most importantly, relatively low concentrations of DIF-1 (1-5 microM) were found to promote retinoic acid-induced cell differentiation. The present results indicate that DIF-1 may be a useful tool for the analysis of myeloid cell differentiation and have therapeutic potential in the treatment of human myeloid leukemia.

To fully describe the clinical course of lupus nephritis in an African-American population, we report our experience with 54 patients seen at a large inner-city hospital over a period of 14 years. The patients were divided into five histopathologic groups. Group MES (n = 3) represented mesangial nephritis (World Health Organization [WHO] class II) and group FOC (n = 11) represented mild and moderate focal segmental proliferative glomerulonephritis (WHO class III). Group DIF (n = 9) included patients with severe segmental proliferative, diffuse proliferative, membranoproliferative, and membranous and severe superimposed proliferative lesions (WHO classes III, IV, and Vd). Group CRES (n = 9) combined all the patients with cellular crescents in more than 40% of the glomeruli and included patients in WHO classes III (severe), IV, and Vc and d. Group MEM (n = 22) represented membranous nephritis occurring alone or with superimposed mesangial or mild segmental proliferative lesions (WHO class Va and b). Groups DIF and CRES received intensive treatment with high-dose prednisone and cytotoxic drugs. Groups FOC and MEM received lower doses of prednisone, but half of the patients later received intensive treatment largely for severe systemic manifestations. The three patients in group MES remained well. End-stage renal failure (ESRF) developed in 11 of 18 patients in groups DIF and CRES combined, and in two of 22 patients in group MEM. Three of 11 patients in group FOC, five in groups DIF and CRES, and one in group MEM died. The actuarial 5- and 10-year survival rates were, respectively, 78% and 78% for FOC, 80% and 0% for DIF and CRES, and 100% and 100% for MEM (P < 0.03 v DIF/CRES). Five- and 10-year survival rates without ESRF were, respectively, 78% and 78% for FOC, 52% and 0% for DIF and CRES (P < 0.05), and 94% and 85% for MEM (P = 0.002 v DIF/CRES). Univariate proportional hazards regression analysis, uncontrolled for histopathologic groups, showed a significant association between ESRF and severe thrombocytopenia (P = 0.003), serum creatinine above 1.4 mg/dL at entry (P = 0.04), and severe systemic manifestations (P = 0.05). After controlling for histopathologic groups, only thrombocytopenia remained strongly associated with ESRF, both by univariate (P = 0.01) and multivariate (hazard ratio = 14.19, P = 0.05) analyses. We conclude that severe proliferative lupus nephritis in African-Americans has a poor prognosis. For mild and moderate focal proliferative nephritis and uncomplicated membranous lupus nephritis the prognosis is as good as in white patients. Severe thrombocytopenia predicts ESRF.

OBJECTIVE

Aim of this study was to evaluate the prevalence of self-mutilation (SM) in Turkish male substance-dependent patients, and to investigate the relationship of SM with childhood abuse and neglect, alexithymia and temperament and character dimensions of personality.

METHODS

Participants were 136 consecutively admitted males with substance dependence (96 alcohol and 40 drug). Substance dependence was diagnosed by means of the Structured Clinical Interview for DSM-IV (SCID-I), Turkish version. Patients were investigated with the childhood abuse and neglect questionnaire, Toronto alexithymia scale (TAS-20) and temperament and character inventory (TCI).

RESULTS

Among substance-dependent patients 34.6% was considered as a group with SM. Rates of being single and unemployed, histories of physical and sexual abuse and suicide attempts were higher in the SM group. Current age, age at first substance use and age at regular substance use were lower in the group with SM. Mean of TAS-20 and 'difficulty in identifying feelings' (DIF) and 'difficulty in describing feelings' (DDF) subscales of TAS-20 were higher in SM group. There were no significant differences between groups in terms of TCI subscales. Age, childhood physical abuse and suicide attempt history predicted SM in logistic regression.

CONCLUSIONS

Young substance users with childhood physical abuse histories could be the target population to prevent self-mutilating behavior. This study also suggests that whenever self-mutilating behavior is present, the possibility of childhood abuse, alexithymia and suicide attempts must be evaluated.

Difloxacin (DIF) belongs to the class of fluoroquinolone antibiotics that have been intensively used for the treatment of bacterial infections in veterinary and human medicine. The aim of this field study was to compare the effect of manure from DIF-treated pigs and untreated pigs on the bacterial community structure and resistance gene abundance in bulk soil and rhizosphere of maize. A significant effect of DIF manure on the bacterial community composition in bulk soil was revealed by denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA gene fragments amplified from total community DNA. In few samples, quinolone resistance genes qnrB and qnrS1/qnrS2 were detected by PCR and subsequent hybridization, while qnrA was not detected. Quantitative PCR revealed an increased abundance of the integrase gene intI1 of class I integrons and sulfonamide resistance genes sul1 and sul2 in DIF manure-treated bulk soil and rhizosphere, relative to 16S rRNA genes, while traN genes specific for LowGC-type plasmids were increased only in bulk soil. Principal component analysis of DGGE profiles suggested a manure effect in soil until day 28, but samples of days 71 and 140 were found close to untreated soil, indicating resilience of soil community compositions from disturbances by manure.

BACKGROUND

This study investigated (a) the utility of a cigarette quantity-frequency (QF) use criterion as an indicator for nicotine dependence (ND) and (b) the stability of the ND continuum of severity over time.

METHODS

Data from individuals who smoked cigarettes in the year prior to both time points of the National Epidemiologic Survey on Alcohol and Related Conditions were analyzed (n = 6,185). The Alcohol Use Disorder and Associated Disabilities Interview Schedule DSM-IV Version (AUDADIS-IV) assessed for DSM-IV ND and nicotine use. Three QF criteria were created to represent daily consumption of>> or = 5 cigarettes,>> or = 10 cigarettes, or>> or = 20 cigarettes. Confirmatory factor analysis and item response theory analysis were used to explore the latent structure of ND. Differential item functioning (DIF) analysis investigated the stability of the ND continuum over time.

RESULTS

A one-factor model, representing the DSM-IV conceptualization of ND, was an acceptable fit to the data at both time points. The inclusion of QF criteria decreased the fit of the one-factor model of ND. DIF in the severity and discrimination parameters of the diagnostic criteria was evident across the time points of the survey.

CONCLUSIONS

Although QF of cigarette use is related to ND, it appears to be a separate construct. Researchers using the AUDADIS-IV should be aware that the characteristics of the DSM-IV ND criteria do vary slightly across time, even though the changes appear to be relatively small and of minor clinical or practical significance.

OBJECTIVE

To analyse cross-culture validity of the Functional Independence Measure (FIM) in patients with a spinal cord injury using a modern psychometric approach.

METHODS

A total of 19 rehabilitation facilities from four countries in Europe.

METHODS

A total of 647 patients at admission, median age 46 years, 69% male.

METHODS

Data from the FIM, collected on inpatient admission, was fitted to the Rasch model. A detailed analysis of scoring functions of the seven categories of the FIM items was undertaken before to testing fit to the model. Categories were rescored where necessary. Fit to the model was assessed initially within country, and then in the pooled data. Analysis of differential item functioning (DIF) was undertaken in the pooled data for each of the FIM motor and social cognitive scales, respectively. Final fit to the model was tested for breach of local independence by principle components analysis (PCA).

RESULTS

The present scoring system for the FIM motor and cognitive scales, that is a seven category scale, was found to be invalid, necessitating extensive rescoring. Following this, DIF was found in a number of items within the motor scale, requiring a complex solution of splitting items by country to allow for the valid pooling of data. Five country-specific items could not be retained within this solution. The FIM cognitive scale fitted the Rasch model after rescoring, but there was a substantial ceiling effect.

CONCLUSIONS

Data from the FIM motor scale for patients with spinal cord injury should not be pooled in its raw form, or compared from country to country. Only after fit to the Rasch model and necessary adjustments could such a comparison be made, but with a loss of clinical important items. The FIM cognitive scale works well following rescoring, and data may be pooled, but many patients were at the maximum score.

Pharmaceutical agents are often used to stimulate new bone formation for the treatment of bone injuries or diseases (such as osteoporosis). However, there are several problems associated with current orthopedic drug delivery methods. First, conventional systemic administration of pharmaceutical agents may not effectively reach targeted sites and, thus, they can cause nonspecific bone formation in areas not affected by injury or disease. Second, even if intentionally delivered or implanted locally to the damaged bone tissue, these agents tend to rapidly diffuse into adjacent tissues due to weak physical bonding to their drug carriers, which limits their potential to promote prolonged bone formation in targeted areas of bone disease. Therefore, in this study, biodegradable ceramic/polymer nanocomposites were explored as novel drug carriers for orthopedic applications to prolong local drug release and, thus, improve drug effectiveness at bone disease sites. Specifically, a bone morphogenetic protein (BMP-7) derived peptide (DIF-7c) was used as a model drug in this study and was first loaded onto nanocrystalline hydroxyapatite (nano-HA) by either covalent chemical attachment or physical adsorption. These drug-carrying nano-HA particles were then dispersed into a degradable polymer (poly-lactide-co-glycolide or PLGA) matrix to create an implantable system capable of long-term drug release. The aminophase silane covalent chemical immobilization process was utilized in this study. These nanocomposite-based drug delivery systems were then characterized for drug loading efficiency and in vitro drug release. Results demonstrated that DIF-7c was successfully immobilized onto nano-HA placed in PLGA. Moreover, a greater prolonged two-phase release profile (of more than 3 months) was achieved when using aminophase silane chemical immobilization to nano-HA particles. Since previous studies have demonstrated greater in vivo bone growth on nano- compared with micron-HA particles placed in rat calvaria, this study continued to demonstrate that ceramic/polymer nanocomposites are promising candidates as novel orthopedic materials to promote bone regeneration.

OBJECTIVE

Cognitive dysfunction is a common concern for children with brain tumors (BTs) or those receiving central nervous system (CNS) toxic cancer treatments. Perceived cognitive function (PCF) is an economical screening that may be used to trigger full, formal cognitive testing. We assessed the potential clinical utility of PCF by comparing parent-reported scores for children with cancer with scores from the general US population.

METHODS

Children (n = 515; mean age = 13.5 years; 57.0 % male) and one of their parents were recruited from pediatric oncology clinics. Most children (53.3 %) had a diagnosis of CNS tumor with an average time since diagnosis of 5.6 years. PCF was evaluated using the pediatric PCF item bank (pedsPCF), which was developed and normed on a sample drawn from the US general pediatric population. Children also completed computer-based neuropsychological tests. We tested relationships between PCF and clinical variables. Differential item functioning (DIF) was used to evaluate measurement bias between the samples.

RESULTS

No item showed DIF, supporting the use of pedsPCF in the cancer sample. PedsPCF differentiated children with (vs. without) a BT, p < 0.01, and groups defined by years since diagnosis, p < 0.01. It significantly (p < 0.05) correlated with computerized neuropsychological tests in 40 of 60 comparisons. Children with BTs were rated as having worse pedsPCF scores than the norm, regardless of years since diagnosis.

CONCLUSIONS

PCF significantly differentiated cancer survivors with various clinical characteristics. It is brief and easy to implement. PCF should be considered for routine care of pediatric cancer survivors.

BACKGROUND

In most of the world, cannabis smokers mix loose tobacco inside a joint, pipe, spliff, or cone. More recently, a 'blunt' formulation combines these two drugs by inserting cannabis into a hollowed-out cigar. Epidemiological research linking simultaneous use of these two drugs and the development of cannabis use disorders (CUD) remains unclear. This study estimates associations linking blunt smoking with levels and subtypes of cannabis problems.

METHODS

Cross-sectional data on 27,767 past-year cannabis users were analyzed from the US National Survey on Drug Use and Health (NSDUH) conducted from 2009 to 2012. Ten self-reported items of DSM-IV CUD features elicited a single latent trait of cannabis problem (CP) severity, which was then regressed on past-year blunt smoking and past-month blunt frequency measures within the context of a conceptual model. Differential item functioning (DIF) analysis evaluated potential bias in CP feature response by blunt smoking history.

RESULTS

Past-year blunt smoking was associated with higher CP severity compared to cannabis users who did not smoke blunts. Days of blunt smoking in the past month also predicted higher CP severity than less frequent blunt use. Those smoking blunts experienced more subjectively felt tolerance and having spent more time obtaining or using cannabis, but were less likely to experience other problems, even at the same level of CP severity.

CONCLUSIONS

These findings suggest smoking blunts might promote the development of problematic cannabis use. Responses to cannabis problems differed by history of blunt smoking, possibly implicating an influence of tobacco on measurement of cannabis use disorders.

This study applies a latent variable approach to examine gender and racial/ethnic differences in cocaine dependence, to determine the presence of differential item functioning (DIF) or item-response bias to diagnostic questions of cocaine dependence, and to explore the effects of DIF on the predictor analysis of cocaine dependence. The analysis sample included 682 cocaine users enrolled in two national multisite studies of the National Drug Abuse Treatment Clinical Trials Network (CTN). Participants were recruited from 14 community-based substance abuse treatment programs associated with the CTN, including 6 methadone and 8 outpatient nonmethadone programs. Factor and multiple indicators-multiple causes (MIMIC) procedures evaluated the latent continuum of cocaine dependence and its correlates. MIMIC analysis showed that men exhibited lower odds of cocaine dependence than women (regression coefficient, beta = -0.34), controlling for the effects of DIF, years of cocaine use, addiction treatment history, comorbid drug dependence diagnoses, and treatment setting. There were no racial/ethnic differences in cocaine dependence; however, DIF by race/ethnicity was noted. Within the context of multiple community-based addiction treatment settings, women were more likely than men to exhibit cocaine dependence. Addiction treatment research needs to further evaluate gender-related differences in drug dependence in treatment entry and to investigate how these differences may affect study participation, retention, and treatment response to better serve this population.

A putative morphogen, called differentiation-inducing factor (DIF), is essential for stalk cell differentiation in the cellular slime mold, Dictyostelium discoideum. To investigate the relationship between the signal molecule (DIF) and the concentrations of cytoplasmic calcium ions and proton, we have examined the effects of thapsigargin (Tg) and 5,5-dimethyl-2,4-oxazolidinedione (DMO) on cell differentiation of a mutant strain HM44, which is defective in DIF production. Tg is a specific inhibitor of the Ca(2+)-ATPase present in endoplasmic and sarcoplasmic reticula, and raises the cytoplasmic calcium concentration. DMO is a reagent that decreases intracellular pH. When HM44 cells were incubated with Tg or DMO in the absence of DIF, a fraction of the cells was induced to stalk cells. If added together, these reagents induced stalk cell differentiation at high efficiency (70-80%), comparable to that attained with exogenous DIF. In the presence of the reagents, the efficiency was not much affected by lowering cell density, which suggests that the effect (stalk induction) of these reagents was not exerted through the stimulation of DIF production. Thus, these results indicate that a rise in cytoplasmic calcium and proton concentrations triggers stalk cell differentiation possibly by mimicking the roles of DIF.

A pot experiment was carried out to investigate the impact of Cd and Zn extractability in soil and speciation in pore water of industrial contaminated soils, on metal concentration in a metal sensitive species like spinach (Spinacia oleracea) and a more metal tolerant species like Italian ryegrass (Lolium multiflorum). For chemical speciation of Cd and Zn in pore water, WHAM/Model VI version 6.0 was used. The DGT technique was used to determine the effective concentration, C(E), of Cd and Zn in soils. The free ion activity in pore water correlated well with the contents in plants, and there was a linear relationship between the C(E) values and the concentration of Cd and Zn in both spinach and ryegrass in the non-toxic range. However, the C(E) values usually overestimated the plant contents when plants, particularly the spinach plants, were subjected to toxic concentration in the pore water. Metal uptake decreased in plants affected by toxicity, whereas metal binding to the Chelex resin did not. Thus, we found no linear relationship between the C(E) and metal contents in spinach, whereas a linear relationship was found between C(E)-Zn and the Zn concentration in ryegrass (r2=0.96, p<0.001). For Cd in ryegrass this relationship was weak (r2=0.53, p=0.18). This study indicates that the transport of metals from labile metal pools to the DGT-resin is linearly related to plant uptake only when plants are growing well, and that the applicability of DGT as an indicator for plant uptake seems species dependent.

A systematic study of selective analyte focusing in a multisection electrolyte system by capillary electrophoresis (CE) is presented. It was found that a dynamic pH junction between sample and background electrolyte zones can be used to focus zwitterionic catecholamines and weakly acidic compounds without the use of special ampholytes. Differences in pH and concentration of complexing agents, such as borate, in the sample and background electrolyte zones were determined to cause focusing through changes in the local velocity of the analyte in two different segments of the capillary. Velocity-difference induced focusing (V-DIF) of analytes using a dynamic pH junction allowed the injection of large sample volumes and significantly improved the concentration sensitivity of CE. Under optimized conditions, the limit of detection for epinephrine was determined to be about 4 x 10(-8) M (the original sample) with conventional UV absorbance detection. Moreover, separation efficiencies greater than a million theoretical plates can be achieved by focusing such large sample volumes into narrow zones. Multisection electrolyte systems, which lead to the formation of a dynamic pH junction, can be tuned toward improving the concentration sensitivity of specific analytes if their chemical properties are known.

BACKGROUND

Linear IgA bullous dermatosis (LABD) is a rare autoimmune blistering skin disorder characterized by linear deposits of IgA along the dermoepidermal junction, visualized by direct immunofluorescence (DIF). It is usually spontaneous and drug induced.

OBJECTIVE

To compare the clinical and histological forms of LABD.

METHODS

This retrospective single-centre cohort study concerned 28 patients diagnosed with LABD between 1 January 1995 and 31 December 2010. Imputability, determined according to the French imputability method (modified Bégaud score) and Naranjo score, enabled classification into drug-induced and spontaneous LABD groups. Clinical and histological features were compared by blinded analysis of images and histological patterns.

RESULTS

Sixteen patients had spontaneous LABD and 12 had drug-induced LABD. Nikolsky sign and large erosions were significantly more frequent in drug-induced than spontaneous LABD (P = 0.003 and P = 0.03, respectively), with no between-group differences for erythematous plaques, target or target-like lesions, string of pearls, location, mucosal involvement or histological features.

CONCLUSIONS

Drug-induced LABD was more severe than the spontaneous form, with lesions mimicking toxic epidermal necrolysis. Because LABD may be polymorphic and sometimes life threatening, DIF assay is recommended for all patients with Nikolsky sign and large erosions.

Increases in the availability of gambling heighten the need for a short screening measure of problem gambling. The Problem Gambling Severity Index (PGSI) is a brief measure that allows for the assessment of characteristics of gambling behavior and severity and its consequences. The authors evaluate the psychometric properties of the PGSI using item response theory methods in a representative sample of the urban adult population in South Africa (N = 3,000). The PGSI items were evaluated for differential item functioning (DIF) due to language translation. DIF was not detected. The PGSI was found to be unidimensional, and use of the nominal categories model provided additional information at higher values of the underlying construct relative to a simpler binary model. This study contributes to the growing literature supporting the PGSI as the screen of choice for assessing gambling problems in the general population.

BACKGROUND

Direct immunofluorescence (DIF), indirect immunofluorescence (IIF), and enzyme-linked immunosorbent assay (ELISA) are used for the laboratory diagnosis of bullous pemphigoid (BP).

OBJECTIVE

The diagnostic value of DIF and IIF on rabbit and monkey esophagus or human salt-split skin and commercial ELISAs was assessed.

METHODS

This was a single-center retrospective study where 313 patients with BP were compared with 488 control subjects.

RESULTS

DIF was the most sensitive test (90.8%) whereas sensitivities for IIF on rabbit esophagus, IIF on monkey esophagus, IIF on salt-split skin, BP180 ELISA, and BP230 ELISA were 76.0%, 73.2%, 73.3%, 72.0%, and 59.0%, respectively. The sensitivity of the serologic tests was 88.8% altogether. The specificities for DIF, IIF on rabbit esophagus, IIF on monkey esophagus, IIF on salt-split skin, BP180 ELISA, and BP230 ELISA were 98%, 96.5%, 97.1%, 100%, 94.1%, and 99.2%, respectively.

CONCLUSIONS

The retrospective nature of study was a limitation. Correlation of diagnostic data with clinical manifestations or disease course was not possible.

CONCLUSIONS

In suspected BP, both serologic tests and DIF have to be performed because of a sensitivity issue. Although the ELISAs had a relatively low sensitivity, the serologic tests altogether almost reached the level of sensitivity of DIF. The specificities of all assays were excellent.

The differentiation-inducing factor-1 (DIF-1) is a lipophilic signal molecule (chlorinated alkylphenone) that induces stalk-cell differentiation in the cellular slime mould Dictyostelium discoideum. It has also been shown that DIF-1 and its derivative (DIF-3) suppress cell growth in mammalian tumor cells. In the present study, in order to assess the chemical structure-effect relationship of DIF derivatives and to develop useful agents for the study of both Dictyostelium development and cancer biology, we synthesized 28 analogues of DIF-1 and DIF-3 and investigated their stalk-cell-inducing activity in Dictyostelium HM44 cells (mutant strain) and anti-proliferative activity in human leukemia K562 cells. HM44 cells are defective in endogenous DIF-1 production and should be suitable for the assay for stalk-cell-inducing activity of DIF analogues. DIF-1 and some of its derivatives at nanomolar levels were good stalk-cell inducers in HM44 cells, whereas DIF-3 and some DIF-3 derivatives at micromolar levels were potent anti-proliferative agents in K562 cells. We also tried to search for antagonistic molecules against DIF-1 and DIF-3 but failed to find such molecules from the analogues used here. The present findings would give us hints for identifying the target molecule(s) of DIFs and also for developing novel anti-cancer drugs.

The authors report differential item functioning (DIF) between Black and White participants completing the 60-item Padua Inventory (PI) for obsessive-compulsive disorder (OCD). The authors use an Internet-generated sample that included 105 Blacks, 67 Hispanics, 582 Whites, and 136 additional participants reporting an OCD diagnosis. Factor analysis replicated prior work indicating the PI consists of four factors: contamination fears, checking behaviors, impaired control over thoughts, and fear of losing control over impulses. On the contamination subscale, nonclinical Black and Hispanic mean scores were as high as the OCD group. Comparing Blacks to Whites, the authors applied an item response theory, DIF-graded response model to each factor and found significant DIF on eight items, with biased items in each factor. Results suggest that extraneous factors contribute to racial differences on scores. Cultural practices and fear of being negatively stereotyped may contribute to item bias.

Infrared differential thermal analysis (IDTA) and differential imaging chlorophyll fluorescence (DIF) were employed simultaneously to study the two-dimensional pattern of ice propagation in leaves and mesophyll freeze dehydration as detected by a significant increase of basic chlorophyll fluorescence (F(0)). IDTA and DIF technique gave different insights into the freezing process of leaves that was highly species-specific. IDTA clearly visualized the freezing process consisting of an initial fast spread of ice throughout the vascular system followed by mesophyll freezing. While mesophyll freezing was homogeneously in Poa alpina, Rhododendron ferrugineum and Senecio incanus as determined by IDTA, DIF showed a distinct pattern only in S. incanus, with the leaf tips being affected earlier. In Cinnamomum camphora, a mottled freezing pattern of small mesophyll compartments was observed by both methods. In IDTA images, a random pattern predominated, while in DIF images, compartments closer to lower order veins were affected earlier. The increase of F(0) following mesophyll freezing started after a species-specific time lag of up to 26 min. The start of the F(0) increase and its slope were significantly enhanced at lower temperatures, which suggest a higher strain on mesophyll protoplasts when freezing occurs at lower temperatures.

Measurement equivalence is a necessary assumption for meaningful comparison of pediatric quality of life rated by children and parents. In this study, differential item functioning (DIF) analysis is used to examine whether children and their parents respond consistently to the items in the KINDer Lebensqualitätsfragebogen (KINDL; in German, Children Quality of Life Questionnaire). Two DIF detection methods, graded response model (GRM) and ordinal logistic regression (OLR), were applied for comparability. The KINDL was completed by 1,086 school children and 1,061 of their parents. While the GRM revealed that 12 out of the 24 items were flagged with DIF, the OLR identified 14 out of the 24 items with DIF. Seven items with DIF and five items without DIF were common across the two methods, yielding a total agreement rate of 50 %. This study revealed that parent proxy-reports cannot be used as a substitute for a child's ratings in the KINDL.

BACKGROUND

Previous studies have analyzed the psychometric properties of the World Health Organization Disability Assessment Schedule II (WHO-DAS II) using classical omnibus measures of scale quality. These analyses are sample dependent and do not model item responses as a function of the underlying trait level. The main objective of this study was to examine the effectiveness of the WHO-DAS II items and their options in discriminating between changes in the underlying disability level by means of item response analyses. We also explored differential item functioning (DIF) in men and women.

METHODS

The participants were 3615 adult general practice patients from 17 regions of Spain, with a first diagnosed major depressive episode. The 12-item WHO-DAS II was administered by the general practitioners during the consultation. We used a non-parametric item response method (Kernel-Smoothing) implemented with the TestGraf software to examine the effectiveness of each item (item characteristic curves) and their options (option characteristic curves) in discriminating between changes in the underliying disability level. We examined composite DIF to know whether women had a higher probability than men of endorsing each item.

RESULTS

Item response analyses indicated that the twelve items forming the WHO-DAS II perform very well. All items were determined to provide good discrimination across varying standardized levels of the trait. The items also had option characteristic curves that showed good discrimination, given that each increasing option became more likely than the previous as a function of increasing trait level. No gender-related DIF was found on any of the items.

CONCLUSIONS

All WHO-DAS II items were very good at assessing overall disability. Our results supported the appropriateness of the weights assigned to response option categories and showed an absence of gender differences in item functioning.