Accumulation of carbon disulphide metabolites

Summary Biological monitoring for carbon disulphide (CS₂) exposure performed using the iodine-azide test (IAT) and 2-thiothiazolidine-4-carboxylic acid (TTCA) test in urinalysis of workers with high exposure to CS₂ (112–142 mg/m³, n = 34), workers with low exposure (4–7 mg/m³, n = 16), and non-exposed university workers (n =10). Pre-shift and post-shift urine specimens were collected on three consecutive days in the exposed and for only one day in the non-exposed. According to the findings the specificity and the sensitivity seem to be low for the IAT and high for the TTCA test. Contrary to a previous report all pre-shift urine samples showed negative IATs. The TTCA test was positive in pre-shift urine even after 32 to 63.5 h without exposure, and values tended to increase during consecutive days of exposure in highly exposed workers.The possible health implications of these findings should be further investigated.     

Brain CT perfusion improves intracranial vessel occlusion detection on CT angiography

Background and purpose

To evaluate whether brain CT perfusion (CTP) aids in the detection of intracranial vessel occlusion on CT angiography (CTA) in acute ischemic stroke.

Internet Addiction Test (IAT): Which is the Best Factorial Solution?

Background

The Internet Addiction Test (IAT) by Kimberly Young is one of the most utilized diagnostic instruments for Internet addiction. Although many studies have documented psychometric properties of the IAT, consensus on the optimal overall structure of the instrument has yet to emerge since previous analyses yielded markedly different factor analytic results.

Objective

The objective of this study was to evaluate the psychometric properties of the Italian version of the IAT, specifically testing the factor structure stability across cultures.

Methods

In order to determine the dimensional structure underlying the questionnaire, both exploratory and confirmatory factor analyses were performed. The reliability of the questionnaire was computed by the Cronbach alpha coefficient.

Results

Data analyses were conducted on a sample of 485 college students (32.3%, 157/485 males and 67.7%, 328/485 females) with a mean age of 24.05 years (SD 7.3, range 17-47). Results showed 176/485 (36.3%) participants with IAT score from 40 to 69, revealing excessive Internet use, and 11/485 (1.9%) participants with IAT score from 70 to 100, suggesting significant problems because of Internet use. The IAT Italian version showed good psychometric properties, in terms of internal consistency and factorial validity. Alpha values were satisfactory for both the one-factor solution (Cronbach alpha=.91), and the two-factor solution (Cronbach alpha=.88 and Cronbach alpha=.79). The one-factor solution comprised 20 items, explaining 36.18% of the variance. The two-factor solution, accounting for 42.15% of the variance, showed 11 items loading on Factor 1 (Emotional and Cognitive Preoccupation with the Internet) and 7 items on Factor 2 (Loss of Control and Interference with Daily Life). Goodness-of-fit indexes (NNFI: Non-Normed Fit Index; CFI: Comparative Fit Index; RMSEA: Root Mean Square Error of Approximation; SRMR: Standardized Root Mean Square Residual) from confirmatory factor analyses conducted on a random half subsample of participants (n=243) were satisfactory in both factorial solutions: two-factor model (χ² ₁₃₂= 354.17, P<.001, χ²/df=2.68, NNFI=.99, CFI=.99, RMSEA=.02 [90% CI 0.000-0.038], and SRMR=.07), and one-factor model (χ² ₁₆₉=483.79, P<.001, χ²/df=2.86, NNFI=.98, CFI=.99, RMSEA=.02 [90% CI 0.000-0.039], and SRMR=.07).

Conclusions

Our study was aimed at determining the most parsimonious and veridical representation of the structure of Internet addiction as measured by the IAT. Based on our findings, support was provided for both single and two-factor models, with slightly strong support for the bidimensionality of the instrument. Given the inconsistency of the factor analytic literature of the IAT, researchers should exercise caution when using the instrument, dividing the scale into factors or subscales. Additional research examining the cross-cultural stability of factor solutions is still needed.     

The relation between race-related implicit associations and scalp-recorded neural activity evoked by faces from different races

Abstract

The neural correlates of the perception of faces from different races were investigated. White participants performed a gender identification task in which Asian, Black, and White faces were presented while event-related potentials (ERPs) were recorded. Participants also completed an implicit association task for Black (IAT-Black) and Asian (IAT-Asian) faces. ERPs evoked by Black and White faces differed, with Black faces evoking a larger positive ERP that peaked at 168 ms over the frontal scalp, and White faces evoking a larger negative ERP that peaked at 244 ms. These Black/White ERP differences significantly correlated with participants’ scores on the IAT-Black. ERPs also differentiated White from Asian faces and a significant correlation was obtained between the White-Asian ERP difference waves at ~500 ms and the IAT-Asian. A positive ERP at 116 ms over occipital scalp differentiated all three races, but was not correlated with either IAT. In addition, a late positive component (around 592 ms) was greater for the same race compared to either other race faces, suggesting potentially more extended or deeper processing of the same race faces. Taken together, the ERP/IAT correlations observed for both other races indicate the influence of a race-sensitive evaluative process that may include early more automatic and/or implicit processes and relatively later more controlled processes.     

Retraining automatic action‐tendencies to approach alcohol in hazardous drinkers

Aims The main aim of this study was to test whether automatic action‐tendencies to approach alcohol can be modified, and whether this affects drinking behaviour. Design and participants Forty‐two hazardous drinkers were assigned randomly to a condition in which they were implicitly trained to avoid or to approach alcohol, using a training variety of the alcohol Approach Avoidance Test (AAT). Participants pushed or pulled a joystick in response to picture‐format (landscape or portrait). The pictures depicted alcoholic or non‐alcoholic drinks. Participants in the avoid‐alcohol condition pushed most alcoholic and pulled most non‐alcoholic drinks. For participants in the approach‐alcohol condition these contingencies were reversed. After the implicit training, participants performed a taste test, including beers and soft drinks. Automatic action tendencies at post‐test were assessed with the AAT, including both trained and untrained pictures, and with a different test (Implicit Association Test, IAT). We further tested effects on subjective craving. Results Action tendencies for alcohol changed in accordance with training condition, with the largest effects in the clinically relevant avoid‐alcohol condition. These effects occurred outside subjective awareness and generalized to new pictures in the AAT and to an entirely different test using words, rather than pictures (IAT). In relatively heavy drinking participants who demonstrated changed action tendencies in accordance with their training condition, effects were found on drinking behaviour, with participants in the approach‐alcohol condition drinking more alcohol than participants in the avoid‐alcohol condition. No effect was found on subjective craving. Conclusions Retraining automatic processes may help to regain control over addictive impulses, which points to new treatment possibilities.     

First example of anti-Kx in a person with the McLeod phenotype and without chronic granulomatous disease

BACKGROUND: Kx is lacking in the RBCs of patients with the McLeod syndrome. This condition is sometimes associated with chronic granulomatous disease (CGD). If given allogeneic RBCs, CGD patients with the McLeod phenotype may produce anti-Kx and anti-Km, and only phenotypically matched McLeod blood would be compatible. McLeod phenotype persons without CGD have made anti-Km but not anti-Kx (2 examples), and thus both McLeod and K(O) blood would be compatible. CASE REPORT: RBCs from a transfused patient with the McLeod phenotype but not with CGD (non-CGD McLeod) were typed for the Kell blood group antigens, and the plasma was analyzed for the presence of antibody by agglutination. The molecular basis was determined by analyzing for XK protein on RBC membranes by Western immunoblotting, by sequencing the XK gene, and by RFLP. RESULTS: The RBCs did not react with anti-Kx + anti-Km and showed weakening of Kell system antigens. The patient's plasma reacted moderately (2+) with RBCs of common Kell type and strongly (4+) with K(O) RBCs and RBCs of common Kell type treated with dithiothreitol, and did not react with McLeod RBCs. XK protein was absent from the RBC membranes. The XK gene had a point mutation in the donor splice site of intron 1 (G>C). CONCLUSION: This is the first report describing the molecular alteration in a non-CGD McLeod patient who has made anti-Kx. The immune response of people with the McLeod phenotype can vary, and K(O) blood may not always be compatible.     

A MAR-like antibody in a DCWe/DCWe person

BACKGROUND: MAR (RH51), a high-incidence antigen in the Rh blood group system, is absent from RBCs with a double dose of CW or CX or a single dose each of CW and CX antigens, as well as from rare Rh phenotypes including D- - and Rh(null). The MAR antigen is associated with the presence of Ala36 and Gln41 on the RhCe protein. The original example of anti-MAR, described in 1994, was made by a DCWe/DCXe woman. It was possible that the antibody directed against a high-incidence antigen in the Rh system made by a DCXe/DCXe woman (CM) in 1983 was anti-MAR. CASE REPORT: A 52-year-old, multiply transfused, white woman (CJ) with pre-existing anti-c, -E, and -Jk(a) presented for preoperative work-up for her fifth open heart procedure. The strength of the reaction of her RBCs with anti-CW suggested a double dose of CW antigen. Her serum, which unexpectedly was strongly reactive with c-, E-, Jk(a-) RBCs by PEG indirect antiglobulin test, was incubated with E-c-, Jk(a-) RBCs, and an eluate was prepared. This eluate reacted 3+ with E-c-, Jk(a-) RBCs but did not react with Rh(null) (n = 5), - - (3), DCW- (2), Dc- (1), or DCWe/DCWe (1) RBCs. Two related DCXe/DCXe and two unrelated DCWe/DCXe RBC samples were weakly agglutinated. The patient's RBCs were negative with the original anti-MAR but reacted as strongly as the positive control RBCs with the antibody made by the DCXe/DCXe person. CONCLUSION: This is the first example of a MAR-like antibody made by a DCWe/DCWe woman. The specificity cannot be called anti-MAR, because some MAR-negative samples react, albeit weakly. The original anti-MAR, made by a DCWe/DCXe woman, did not react with DCWe/DCWe, DCWe/DCXe, or DCXe/DCXe RBCs. It is apparent that the specificity of "anti-MAR" differs slightly, depending on the CW/CX status of the antibody maker.     

Implicit Infantilizing Attitudes About Disability

This study serves as a preliminary investigation of implicit (unconscious) attitudes that associate disability with child-like features. A version of the Implicit Association Test was developed to assess the implicit association of disability-related words with words related to childhood. In order to assess its psychometric properties, this “infantilization IAT” was administered, along with a more evaluative IAT and measures of more explicit attitudes, two times over the course of three to five days to 30 staff persons of a facility that serves persons with multiple disabilities. The study's results: (1) Support the notion that individuals tend to implicitly associate disability-related words with words connoting childhood or child-like features; (2) Suggest that the infantilization IAT assesses attitudes that might not be captured through more traditional measurement strategies, and (3) Demonstrate divergent validity of the infantilization IAT when compared to results of the evaluative IAT, but (4) Also suggest relatively low test-retest reliability of the infantilization IAT.     

Donor-derived alloantibodies and passenger lymphocyte syndrome in two of four patients who received different organs from the same donor

BACKGROUND: Reported here is the occurrence of RBC alloimmunization in two of four patients who received different organs from an immunized donor. STUDY DESIGN AND METHODS: The donor, a 58-year-old woman, was group O D+, K-, and Fy(a-). Initially, her serum contained only a K antibody. After blood transfusion, a second antibody (anti-Fy(a)) could also be identified. The liver was given to a group O D+, K-, Fy(a+) patient; the pancreas and one kidney to a group O D+, K-, Fy(a+) patient; the heart to a group A D+, K-, Fy(a-) patient; and the other kidney to a group B D+, K-, Fy(a+) patient. RBC grouping and antibody screening were performed by standard techniques. Lymphoid microchimerism in the peripheral blood of the recipients was analyzed by flow cytometry and nested PCR. RESULTS: None of the recipients had irregular RBC alloantibodies at the time of transplantation. After the transplant, anti-K became detectable in the serum of the liver recipient, and anti-Fy(a) could be eluted from the RBCs of the liver recipient and the pancreas-kidney recipient. The latter patient also developed mild hemolysis, and his Hb dropped to 8 g per dL on posttransplant Day 9. Donor-derived lymphocytes were detectable by flow cytometry in the peripheral blood of the liver recipient and the pancreas-kidney recipient until Days 8 and 63, respectively, whereas no lymphoid chimerism could be demonstrated in the heart recipient. PCR chimerism analyses were positive in all three recipients over the whole observation period of 97 postoperative days. CONCLUSION: The amount of cotransplanted lymphoid tissue may correlate with the extent of peripheral lymphoid microchimerism and the antibody-formation capacity in solid organ transplantation.