WHAT IS KNOWN ON THE SUBJECT?: The TAS-20 is the most widely used self-reported questionnaire to assess the level of alexithymia in students and community and clinical samples. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: The TAS-20-C exhibited high levels of reliability and validity, indicating that it is appropriate for the assessment of alexithymia in Chinese adolescents. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Screening adolescents who are at risk of alexithymia through the TAS-20 could help to perform necessary and effective precautions to decrease the adverse effects of alexithymia, such as the risks of developing depressive mood and behavioral problems.

UNASSIGNED

Purpose The aim of this study was to examine the psychometric properties of the Chinese version of the 20-item Toronto Alexithymia Scale (TAS-20-C) in a sample of Chinese adolescents. Method Adolescents (n = 1260) recruited from three schools in mainland China completed the TAS-20-C, the somatization subscale of the Symptom Checklist 90 (SCL-90) and Center for Epidemiological Studies Depression Scale (CES-D). Five different factorial models of the TAS-20 were tested using confirmatory factor analysis (CFA). Cronbach's α, mean inter-item correlations and predictive validity were also evaluated. Results Among those five different factorial models, the four-factor structure model was suitable and invariant across gender and age in this sample. The TAS-20-C demonstrated adequate internal reliability. Gender and age accounted for insignificant amounts of variability in total TAS-20-C and factor scores. TAS-20-C total and subscale scores were correlated significantly with SCL-90 somatization subscale and CES-D. Girls scored higher than boys on difficulty identifying feelings (DIF) and pragmatic thinking (PR) subscales. DIF and lack of subjective significance or importance of emotions (IMs) subscale scores were higher among younger than among middle and older adolescents. Implications for Practice Validating the TAS-20 in adolescents is quite important to use it in evaluating adolescents' alexithymia, and screen those at risk of alexithymia.

Direct immunofluorescence (DIF) is widely used for the diagnosis of bullous diseases and other autoimmune pathologies such as oral lichen planus. There is no evidence in the literature on how the following variants influence the detection rate of DIF: intraoral site chosen for the biopsy, perilesional locus or distant site from the clinical lesion, number of biopsies and instrument used.

OBJECTIVE

to determine if the following variants influenced the sensitivity (detection rate): intraoral site chosen for the biopsy, perilesional or distant site from the clinical lesion, number of biopsies and instrument used (punch or scalpel).

METHODS

A retrospective study was done at the Cátedra de Patología y Clínica Bucodental II at the Facultad de Odontología, Universidad de Buenos Aires; 136 clinical medical histories were revised for the period March 2000 - March 2005 corresponding to patients with clinical diagnosis of OLP and bullous diseases (vulgar pemphigus, bullous pemphigoid and cicatricial pemphigoid).

RESULTS

DIF detection rate was 65.8% in patients with OLP, 66.7% in cicatricial pemphigoid patients, in bullous pemphigoid 55.6%, in pemphigus vulgaris 100%, and in those cases in which certain diagnosis could not be obtained, the DIF positivity rate was 45.5% (Pearson chi(2) (4)= 21.5398 Pr= 0.000). There was no statistically significant difference between the different sites of biopsy (Fisher exact test: 0.825). DIF detection rate in perilesional biopsies was 66.1% and in those distant from the site of clinical lesion was 64.7% (Pearson chi(2) v1)= 0.0073 Pr= 0.932. When the number of biopsies were incremented, DIF detection rate also incremented (Pearson chi(2) = 8.7247 Pr= 0.003). The biopsies taken with punch had a higher detection rate than those taken with scalpel (39.1% versus 71.7%) (Pearson chi(2) = 49.0522 Pr= 0.000).

CONCLUSIONS

While not statistically significant, the tendency outlined in this study indicates there are intraoral regions in which the detection rate of the DIF technique is higher than others: mouth floor, hard palate, superior labial mucosa, ventral face of tongue. This finding could allow a choice of accessible locations and easy operator manipulation, even in distant places from the clinical lesion. Perilesional biopsies have a detection rate similar to those taken distant from the clinical lesion, and those taken with punch have a higher sensitivity rate than those taken with scalpel (both differences were statistically significant).

Dermatitis herpetiformis (DH) is an inflammatory disease of the skin, considered the specific cutaneous manifestation of celiac disease (CD). Both DH and CD occur in gluten-sensitive individuals, share the same Human Leukocyte Antigen (HLA) haplotypes (DQ2 and DQ8), and improve following the administration of a gluten-free diet. Moreover, almost all DH patients show typical CD alterations at the small bowel biopsy, ranging from villous atrophy to augmented presence of intraepithelial lymphocytes, as well as the generation of circulating autoantibodies against tissue transglutaminase (tTG). Clinically, DH presents with polymorphic lesions, including papules, vesicles, and small blisters, symmetrically distributed in typical anatomical sites including the extensor aspects of the limbs, the elbows, the sacral regions, and the buttocks. Intense pruritus is almost the rule. However, many atypical presentations of DH have also been reported. Moreover, recent evidence suggested that DH is changing. Firstly, some studies reported a reduced incidence of DH, probably due to early recognition of CD, so that there is not enough time for DH to develop. Moreover, data from Japanese literature highlighted the absence of intestinal involvement as well as of the typical serological markers of CD (i.e., anti-tTG antibodies) in Japanese patients with DH. Similar cases may also occur in Caucasian patients, complicating DH diagnosis. The latter relies on the combination of clinical, histopathologic, and immunopathologic findings. Detecting granular IgA deposits at the dermal-epidermal junction by direct immunofluorescence (DIF) from perilesional skin represents the most specific diagnostic tool. Further, assessing serum titers of autoantibodies against epidermal transglutaminase (eTG), the supposed autoantigen of DH, may also serve as a clue for the diagnosis. However, a study from our group has recently demonstrated that granular IgA deposits may also occur in celiac patients with non-DH inflammatory skin diseases, raising questions about the effective role of eTG IgA autoantibodies in DH and suggesting the need of revising diagnostic criteria, conceivably emphasizing clinical aspects of the disease along with DIF. DH usually responds to the gluten-free diet. Topical clobetasol ointment or dapsone may be also applied to favor rapid disease control. Our review will focus on novel pathogenic insights, controversies, and management aspects of DH.

Transcriptional silencing via promoter methylation of genes important for cell growth and differentiation plays a key role in myeloid leukemogenesis. We find that clinically achievable levels of 5-aza-2'-deoxycytidine (5-AZA-dC), a potent inhibitor of DNA methylation, can modify chromatin and restore the ability of tumor necrosis factor alpha (TNFalpha) to induce monocytic differentiation of the acute myeloid leukemia cells NB4 and U937. Although 5-AZA-dC cannot fully induce differentiation, we show that 5-AZA-dC acts directly on TNFalpha-responsive promoters to facilitate TNFalpha-induced transcriptional pathways leading to differentiation. 5-AZA-dC regulates the expression of Dif-2, a TNFalpha target gene, by deacetylating chromatin domains in a methylation-dependent manner. Chromatin immunoprecipitation analyses of the Dif-2 promoter show histone hyperacetylation and a recruitment of the nuclear factor-kappaB transcription factor in response to 5-AZA-dC. Furthermore, 5-AZA-dC plus TNFalpha enhances the level of phosphorylated RNA Pol II at the Dif-2 promoter via synergistic recruitment of TFIIH. We conclude that nonspecific changes in chromatin can allow a specific transcriptional inducer to overcome blocks in leukemic cell differentiation. Our results support the concept of low doses of 5-AZA-dC acting in combination with other agents to target epigenetic changes that drive malignant growth in leukemic cells. [Cancer Res 2009;69(1):55-64].

Seventy-nine patients presenting with acute epididymo-orchitis (AEO) were prospectively analyzed in order to study the etiology and pattern of the disease. Bacteriological, serological, biochemical, imaging, and endoscopic studies were undertaken to look for urinary tract infection (UTI), brucellosis, gonorrhea, diabetes mellitus (DM), bladder outflow obstruction (BOO), and other urinary tract pathology (UP). Thirty-nine patients also underwent, on their urethral scrapings, the direct immunofluorescence test with monoclonal antibodies (DIF) for Chlamydia trachomatis. The mean age was 44 +/- 20.4 years (median = 40 years) and 43% of the patients were married. Only one patient had urethritis, which nongonococcal. Thirty-five percent presented with pyrexia and only one had brucellosis. Fifty-three percent had significant pyuria but only 22 patients (285) had bacteriuria and E. coli was the etiological agent in 19/22 patients (86%). Eleven out of 39 patients (28%) were positive for Chlamydia trachomatis. BOO, UP, and DM were encountered in 25%, 12.5% and 10%, respectively, but no obvious cause was detected in 26 (33%) patients. Recurrent AEO, abscess formation and bacteremia occurred in 21.5%, 4%, and 1%, respectively. Recurrent AEO was significantly more common in married patients than in single patients (P<0.05) and BOO was significantly more common in patients above the age of 50 years. It is concluded that an underlying cause of AEO could be identified in only two-thirds of the patients. In the remaining one-third, the etiology continues to be obscure and investigations for viral and fastidious infections may be of help in future studies. Endoscopy and urodynamic studies for BOO can be restricted to the elderly patients to cut down the cost of management of this fairly common emergency.

The purpose of this study was to investigate in vivo intestinal precipitation of a model drug mebendazole, a basic BCS class II drug, using dogs with intestinal stomas for administration or sampling. After oral administration of a solution with an expected intestinal supersaturation of approximately 20 times the solubility, the measured supersaturation in dog intestinal fluid (DIF) was up to 10 times and, on average, only 11% of the given dose was retrieved as solid drug in the collected fluid from the stoma. The drug was rapidly absorbed with >90% of the total systemic exposure reached within three hours after duodenal administration of a solution. In silico absorption modeling showed that in vivo data were reasonably well described by a nonprecipitating solution. An in vitro model of precipitation in DIF predicted that the intestinal concentration of dissolved mebendazole would be less than 1/5 of the initial concentration within 10 min at concentrations comparable to in vivo. It was concluded that intestinal precipitation did not have any major influence on mebendazole absorption. The extent of precipitation was overpredicted in vitro given the in vivo absorption rate, and further work is needed to identify in vitro factors that could enable more accurate in vivo predictions of intestinal precipitation from solutions.

OBJECTIVE

To investigate the measurement invariance (MI) of the Family Affluence Scale (FAS) measured in the Health Behavior in School-aged Children (HBSC) survey, and to describe a method for equating the scale when MI is violated across survey years.

METHODS

This study used a sample of 14,076 Norwegian and 17,365 Scottish adolescents from the 2002, 2006 and 2010 HBSC surveys to investigate the MI of the FAS across survey years. Violations of MI in the form of differential item functioning (DIF) due to item parameter drift (IPD) were modeled within the Rasch framework to ensure that the FAS scores from different survey years remain comparable.

RESULTS

The results indicate that the FAS is upwardly biased due to IPD in the computer item across survey years in the Norwegian and Scottish samples. Ignoring IPD across survey years resulted in the conclusion that family affluence is increasing quite consistently in Norway and Scotland. However, the results show that a large part of the increase in the FAS scores can be attributed to bias in the FAS because of IPD across time. The increase in the FAS was more modest in Scotland and slightly negative in Norway once the DIF in the computer item was accounted for in this study.

CONCLUSIONS

When the comparison of family affluence is necessary over different HBSC survey years or when the longitudinal implications of family affluence are of interest, it is necessary to account for IPD in interpretation of changes in family affluence across time.

Improving the charge carrier mobility of solution-processable organic semiconductors is critical for the development of advanced organic thin-film transistors and their application in the emerging sector of printed electronics. Here, a simple method is reported for enhancing the hole mobility in a wide range of organic semiconductors, including small-molecules, polymers, and small-molecule:polymer blends, with the latter systems exhibiting the highest mobility. The method is simple and relies on admixing of the molecular Lewis acid B(C6F5)3 in the semiconductor formulation prior to solution deposition. Two prototypical semiconductors where B(C6F5)3 is shown to have a remarkable impact are the blends of 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene:poly(triarylamine) (diF-TESADT:PTAA) and 2,7-dioctyl[1]-benzothieno[3,2-b][1]benzothiophene:poly(indacenodithiophene-co-benzothiadiazole) (C8-BTBT:C16-IDTBT), for which hole mobilities of 8 and 11 cm2 V-1 s-1, respectively, are obtained. Doping of the 6,13-bis(triisopropylsilylethynyl)pentacene:PTAA blend with B(C6F5)3 is also shown to increase the maximum hole mobility to 3.7 cm2 V-1 s-1. Analysis of the single and multicomponent materials reveals that B(C6F5)3 plays a dual role, first acting as an efficient p-dopant, and secondly as a microstructure modifier. Semiconductors that undergo simultaneous p-doping and dopant-induced long-range crystallization are found to consistently outperform transistors based on the pristine materials. Our work underscores Lewis acid doping as a generic strategy towards high performance printed organic microelectronics.

BACKGROUND

Policies, designed to promote resilience, and research, to understand the determinants and correlates of resilience, require reliable and valid measures to ensure data quality. The student resilience survey (SRS) covers a range of external supports and internal characteristics which can potentially be viewed as protective factors and can be crucial in exploring the mechanisms between protective factors and risk factors, and to design intervention and prevention strategies. This study examines the validity of the SRS.

METHODS

7663 children (aged 11-15 years) from 12 local areas across England completed the SRS, and questionnaires regarding mental and physical health. Psychometric properties of 10 subscales of the SRS (family connection, school connection, community connection, participation in home and school life, participation in community life, peer support, self-esteem, empathy, problem solving, and goals and aspirations) were investigated by confirmatory factor analysis (CFA), differential item functioning (DIF), differential test functioning (DTF), Cronbach's α and McDonald's ω. The associations between the SRS scales, mental and physical health outcomes were examined.

RESULTS

The results supported the construct validity of the 10 factors of the scale and provided evidence for acceptable reliability of all the subscales. Our DIF analysis indicated differences between boys and girls, between primary and secondary school children, between children with or without special educational needs (SEN) and between children with or without English as an additional language (EAL) in terms of how they answered the peer support subscale of the SRS. Analyses did not indicate any DIF based on free school meals (FSM) eligibility. All subscales, except the peer support subscale, showed small DTF whereas the peer support subscale showed moderate DTF. Correlations showed that all the student resilience subscales were negatively associated with mental health difficulties, global subjective distress and impact on health. Random effects linear regression models showed that family connection, self-esteem, problem solving and peer support were negatively associated with all the mental health outcomes.

CONCLUSIONS

The findings suggest that the SRS is a valid measure assessing these relevant protective factors, thereby serving as a valuable tool in resilience and mental health research.

BACKGROUND

Perception-based Likert scale are commonly used to assess household food insecurity. The aim of this study was to evaluate the psychometric properties and external construct validity of the 9-item Food Access Survey Tool (FAST) in a population-based randomized controlled trial.

METHODS

Participating women (n = 11,992) were asked to recall the frequencies of nine food insecurity experiences over the past 6 months on a 5-point Likert scale. The Rasch partial credit model was used to study the item category severity and differential item functioning (DIF) by literacy status, respondents' age, land ownership and household sizes. Principal component analysis (PCA), non-parametric methods, and cumulative ordinal logistic regression models were applied to examine the Rasch model assumptions, namely unidimensionality, monotonicity and measurement invariance (non-DIF).

RESULTS

All items demonstrated good model fit with acceptable values of fit statistics (infit). PCA as well as other indices (Cronbach's alpha = 0.85, scalability coefficient = 0.48) indicated that all items fit in a single statistical dimension. The ordered responses of nine items displayed monotonic increasing item category severity as expected theoretically. All nine items were flagged with statistically significant DIF between key demographic-and socioeconomic subgroups (p < 0.001); however, none of the detected DIF was considered practically significant given small effect sizes (variance explained by group membership and interaction term < 1%). The total summed score over the polytomous FAST was inversely associated with household wealth, dietary diversity score and maternal body mass index, demonstrating external construct validity.

CONCLUSIONS

The polytomous FAST is internally and externally valid tool to measure household food insecurity in rural Bangladesh. Validation of this type of studies are recommended for similar Likert food insecurity scales.

Ambulatory children with cerebral palsy (CP) may present with several gait patterns due to muscular spasticity, commonly with crouch gait. Several factors may contribute to continuous knee flexion during gait, including hamstring and gastrocnemius contracture. In planovalgus foot deformity, the combination of heel equinus, talonavicular joint dislocation, midfoot break and external tibial torsion also contribute to crouch gait as part of lever arm dysfunction. In this retrospective cohort study, we assessed 21 children with CP (34 feet) who underwent planovalgus foot correction as a single level surgery. Fifteen feet underwent subtalar fusion and 19 feet had lateral calcaneal lengthening. Patients who underwent knee, hip or pelvis surgeries were excluded from the study. The aim was to examine the changes in gait pattern and the correlation between the changes of knee flexion at stance phase with the other kinematic and kinetic parameters after foot surgery. Post surgery change of Maximum knee extension at stance (MKE-dif) was the outcome of interest. The magnitude of change in MKE after surgery increased (less crouch after surgery) in patients who had milder preoperative planovalgus feet and higher preoperative ankle maximum dorsiflexion at stance and ankle power. The gain of knee extension after surgery correlated with correction of ankle hyperdorsiflexion and with increase of knee extension at initial contact and knee power. Patients with high preoperative ankle maximum dorsiflexion may benefit from surgical foot deformity correction to achieve decreased ankle dorsiflexion with no knee surgical intervention.

Differentiation-inducing factor-1 (DIF-1) isolated from Dictyostelium discoideum strongly inhibits the proliferation of various mammalian cells through the activation of glycogen synthase kinase-3 (GSK-3). To evaluate DIF-1 as a novel anti-cancer agent for malignant melanoma, we examined whether DIF-1 has anti-proliferative, anti-migratory, and anti-invasive effects on melanoma cells using in vitro and in vivo systems. DIF-1 reduced the expression levels of cyclin D1 and c-Myc by facilitating their degradation via GSK-3 in mouse (B16BL6) and human (A2058) malignant melanoma cells, and thereby strongly inhibited their proliferation. DIF-1 suppressed the canonical Wnt signaling pathway by lowering the expression levels of transcription factor 7-like 2 and β-catenin, key transcription factors in this pathway. DIF-1 also inhibited cell migration and invasion, reducing the expression of matrix metalloproteinase-2; however, this effect was not dependent on GSK-3 activity. In a mouse lung tumor formation model, repeated oral administrations of DIF-1 markedly reduced melanoma colony formation in the lung. These results suggest that DIF-1 inhibits cell proliferation by a GSK-3-dependent mechanism and suppresses cell migration and invasion by a GSK-3-independent mechanism. Therefore, DIF-1 may have a potential as a novel anti-cancer agent for the treatment of malignant melanoma.

OBJECTIVE

Our goal is to determine the ability of multi-parametric magnetic resonance imaging (mpMRI) to differentiate muscle invasive bladder cancer (MIBC) from non-muscle invasive bladder cancer (NMIBC).

METHODS

Patients underwent mpMRI before tumour resection. Four MRI sets, i.e. T2-weighted (T2W) + perfusion-weighted imaging (PWI), T2W plus diffusion-weighted imaging (DWI), T2W + DWI + PWI, and T2W + DWI + PWI + dif-fusion tensor imaging (DTI) were interpreted qualitatively by two radiologists, blinded to histology results. PWI, DWI and DTI were also analysed quantitatively. Accuracy was determined using histopathology as the reference standard.

RESULTS

A total of 82 tumours were analysed. Ninety-six percent of T1-labeled tumours by the T2W + DWI + PWI image set were confirmed to be NMIBC at histopathology. Overall accuracy of the complete mpMRI protocol was 94% in differentiating NMIBC from MIBC. PWI, DWI and DTI quantitative parameters were shown to be significantly different in cancerous versus non-cancerous areas within the bladder wall in T2-labelled lesions.

CONCLUSIONS

MpMRI with DWI and DTI appears a reliable staging tool for bladder cancer. If our data are validated, then mpMRI could precede cystoscopic resection to allow a faster recognition of MIBC and accelerated treatment pathways.

CONCLUSIONS

• A critical step in BCa staging is to differentiate NMIBC from MIBC. • Morphological and functional sequences are reliable techniques in differentiating NMIBC from MIBC. • Diffusion tensor imaging could be an additional tool in BCa staging.

OBJECTIVE

We assessed the validity of a locally adapted Colombian Household Food Security Scale (CHFSS) used as a part of the 2006 evaluation of the food supplement component of the Plan for Improving Food and Nutrition in Antioquia, Colombia (MANA - Plan Departamental de Seguridad Alimentaria y Nutricional de Antioquia).

METHODS

Subjects included low-income families with pre-school age children in MANA that responded affirmatively to at least one CHFSS item (n = 1,319). Rasch Modeling was used to evaluate the psychometric characteristics of the items through measure and INFIT values. Differences in CHFSS performance were assessed by area of residency, socioeconomic status and number of children enrolled in MANA. Unidimensionality of a scale by group was further assessed using Differential Item Functioning (DIF).

RESULTS

Most CHFSS items presented good fitness with most INFIT values within the adequate range of 0.8 to 1.2. Consistency in item measure values between groups was found for all but two items in the comparison by area of residency. Only two adult items exhibited DIF between urban and rural households.

CONCLUSIONS

The results indicate that the adapted CHFSS is a valid tool to assess the household food security of participants in food assistance programs like MANA.

In this issue of Molecular Microbiology, Hendrickson and Lawrence analyse the sequence of bacterial genomes to map the historical traffic pattern of chromosome replication. Their surprising conclusion is that most forks terminate at the dif site rather than at the Tus/Ter sites where most investigators have concluded termination occurs most frequently. What make this analysis novel are the methods and the revisionist hypotheses for how and why forks might stop at dif.

Both the concept and the application of the impact factor (IF) have been subject to widespread critique, including concerns over its potential manipulation. This study provides a systematic analysis of significant journal Impact Factor changes, based on the relative contribution of either one or both variables of the IF equation (i.e. citations / articles as the numerator / denominator of the quotient). A cohort of JCR-listed journals which faced the most dramatic absolute IF changes between 2013 and 2014 (ΔIF ≥ 3.0, n = 49) was analyzed for the causes resulting in IF changes that theses journals have experienced in the last five years. Along with the variation by number of articles and citations, this analysis includes the relative change of both variables compared to each other and offers a classification of `valid`and `invalid`scenarios of IF variation in terms of the intended goal of the IF to measure journal quality. The sample cohort features a considerable incidence of IF increases (18%) which are qualified as `invalid`according to this classification because the IF increase is merely based on a favorably changing number of articles (denominator). The results of this analysis point out the potentially delusive effect of IF increases gained through effective shrinkage of publication output. Therefore, careful consideration of the details of the IF equation and possible implementation of control mechanisms versus the volatile factor of number of articles may help to improve the expressiveness of this metric.

The ecmA gene is expressed in Dictyostelium prestalk cells and is inducible by differentiation-inducing factor (DIF), a low-molecular-weight lipophilic substance. The ecmB gene is expressed in stalk cells and is under negative control by two repressor elements. Each repressor element contains two copies of the sequence TTGA in an inverted relative orientation. There are activator elements in the ecmA promoter that also contain two TTGA sequences, but in the same relative orientation. Gel retardation assays suggest that the same protein binds to the ecmB repressor and the ecmA activator. We propose that DIF induces prestalk cell differentiation by activating this protein and that the protein also binds to the promoters of stalk-specific genes, acting as a repressor that holds cells in the prestalk state until culmination is triggered.

We have compared the searching of the presence of "honeycomb" structures by direct microscopy on wet mount preparations with the direct immunofluorescence (DIF) for the diagnosis of Pneumocystis carinii pneumonia (PCP) in 115 bronchoalveolar (BAL) fluids. The samples belonged to 115 AIDS patients; 87 with presumptive diagnosis of PCP and 28 with presumptive diagnosis other than PCP. The obtained results were coincident in 114 out of 115 studied samples (27 were positive and 87 negative) with both techniques. A higher percentage of positive results (32.18%) among patients with presumptive diagnosis of PCP with respect to those with presumptive diagnosis other than PCP (3.57%) was observed. One BAL fluid was positive only with DIF, showed scarce and isolated P. carinii elements and absence of typical "honeycomb" structures. The searching for "honeycomb" structures by direct microscopy on wet mount preparations could be considered as a cheap and rapid alternative for diagnosis of PCP when other techniques are not available or as screening test for DIF. This method showed a sensitivity close to DIF when it was applied to BAL fluids of AIDS patients with poor clinical condition and it was performed by an experienced microscopist.

BACKGROUND

The Nottingham Health Profile index of Distress (NHPD) has been proposed as a generic undimensional 24-item measure of illness-related distress that is embedded in the Nottingham Health Profile (NHP). Data indicate that the NHPD may have psychometric advantages to the 6-dimensional NHP profile scores. Detailed psychometric evaluations are, however, lacking. Furthermore, to support the validity of the generic property of outcome measures evidence that scores can be interpreted in the same manner in different diagnostic groups are needed. It is currently unknown if NHPD scores have the same meaning across patient populations. This study evaluated the measurement properties and cross-diagnostic validity of the NHPD as a survey instrument among people with Parkinson's disease (PD) and peripheral arterial disease (PAD).

METHODS

Data from 215 (PD) and 258 (PAD) people were Rasch analyzed regarding model fit, reliability, differential item functioning (DIF), unidimensionality and targeting. In cases of cross-diagnostic DIF this was adjusted for and the impact of DIF on the total score and person measures was assessed.

RESULTS

The NHPD was found to have good overall and individual item fit in both disorders as well as in the pooled sample, but seven items displayed signs of cross-diagnostic DIF. Following adjustment for DIF some aspects of model fit were slightly compromised, whereas others improved somewhat. DIF did not impact total NHPD scores or resulting person measures, but the unadjusted scale displayed minor signs of multidimensionality. Reliability was>> 0.8 in all within- and cross-diagnostic analyses. Items tended to represent more distress (mean, 0 logits) than that experienced by the sample (mean, -1.6 logits).

CONCLUSIONS

This study supports the within- and cross-diagnostic validity of the NHPD as a survey tool among people with PD and PAD. We encourage others to reassess available NHP data within the NHPD framework to further evaluate the strengths and weaknesses of this simple patient-reported index of illness-related distress.

BACKGROUND

Measurement scales seeking to quantify latent traits like attitudes, are often developed using traditional psychometric approaches. Application of the Rasch unidimensional measurement model may complement or replace these techniques, as the model can be used to construct scales and check their psychometric properties. If data fit the model, then a scale with invariant measurement properties, including interval-level scores, will have been developed.

OBJECTIVE

This paper highlights the unique properties of the Rasch model. Items developed to measure adolescent attitudes towards abortion are used to exemplify the process.

METHODS

Ten attitude and intention items relating to abortion were answered by 406 adolescents aged 12 to 19 years, as part of the "Teen Relationships Study". The sampling framework captured a range of sexual and pregnancy experiences. Items were assessed for fit to the Rasch model including checks for Differential Item Functioning (DIF) by gender, sexual experience or pregnancy experience.

RESULTS

Rasch analysis of the original dataset initially demonstrated that some items did not fit the model. Rescoring of one item (B5) and removal of another (L31) resulted in fit, as shown by a non-significant item-trait interaction total chi-square and a mean log residual fit statistic for items of -0.05 (SD=1.43). No DIF existed for the revised scale. However, items did not distinguish as well amongst persons with the most intense attitudes as they did for other persons. A person separation index of 0.82 indicated good reliability.

CONCLUSIONS

Application of the Rasch model produced a valid and reliable scale measuring adolescent attitudes towards abortion, with stable measurement properties. The Rasch process provided an extensive range of diagnostic information concerning item and person fit, enabling changes to be made to scale items. This example shows the value of the Rasch model in developing scales for both social science and health disciplines.

OBJECTIVE

To bridge in vitro, in situ and in vivo kinetic analyses of the hepatic clearance of a cyclopentapeptide, BQ-123, by using dispersion models that assume nonlinear pharmacokinetics.

METHODS

Rat livers were perfused by the multiple indicator dilution method with doses of BQ-123 ranging from 1-1000 microg. The outflow dilution curves were fitted to a two-compartment dispersion model that was solved numerically by the finite difference method. Further, in vivo plasma concentrations of BQ-123 after bolus injection were analyzed with a hybrid physiological model that incorporates the hepatic dispersion model.

RESULTS

The calculated Michaelis-Menten constants (Km = 12.0 microM, Vmax = 321 pmol/min/10(6) cells, P(dif) = 1.2 microl/min/10(6) cells) were comparable to those obtained previously from the in vitro isolated hepatocyte experiment (Km = 9.5 microM, Vmax = 517 pmol/min/l0(6) cells, P(dif) = 1.1 microl/min/10(6) cells). The plasma concentrations of BQ-123 at doses of 1-25 mg/kg were explained well by the hybrid physiological model.

CONCLUSIONS

These results suggest that carrier-mediated transport on the sinusoidal membrane was responsible for the in vivo hepatic elimination of BQ-123.

Dimeric chromosomes can be formed during replication of circular bacterial chromosomes by an odd number of homologous recombination events between sister chromosomes. In the absence of a compensating recombination reaction such dimers cannot be segregated from each other as the cell divides. This review highlights the shared and divergent mechanisms employed by Escherichia coli and Bacillus subtilis in their effort to resolve and partition dimeric chromosomes safely. In particular, we discuss the Xer-type recombinases, RecA, FtsK/SpoIIIE, and dif.