Monte Carlo simulation of activity measurement of 123I, 111In and 153Sm with a radionuclide calibrator

The response of radionuclide calibrators for radionuclides with high abundances of high energy X-rays is very sensitive to changes in the source geometry. The magnitude of this effect was explored for Bqmetr (Konsorcium BQM, CR) calibrators with ¹²³I, ¹¹¹In and ¹⁵³Sm in several vial and syringe geometries. Dependencies of chamber responses on solution volume and container position were calculated using MCNP transport code. The possibility of usage of an additional copper filter to reduce chamber sensitivity was studied and found to be suitable.     

Modulation of affective face processing deficits in Schizophrenia by congruent emotional sounds

Schizophrenia is a psychiatric disorder resulting in prominent impairments in social functioning. Thus, clinical research has focused on underlying deficits of emotion processing and their linkage to specific symptoms and neurobiological dysfunctions. Although there is substantial research investigating impairments in unimodal affect recognition, studies in schizophrenia exploring crossmodal emotion processing are rare. Therefore, event-related potentials were measured in 15 patients with schizophrenia and 15 healthy controls while rating the expression of happy, fearful and neutral faces and concurrently being distracted by emotional or neutral sounds. Compared with controls, patients with schizophrenia revealed significantly decreased P1 and increased P2 amplitudes in response to all faces, independent of emotion or concurrent sound. Analyzing these effects with regard to audiovisual (in)congruence revealed that P1 amplitudes in patients were only reduced in response to emotionally incongruent stimulus pairs, whereas similar amplitudes between groups could be observed for congruent conditions. Correlation analyses revealed a significant negative correlation between general symptom severity (Brief Psychiatric Rating Scale-V4) and P1 amplitudes in response to congruent audiovisual stimulus pairs. These results indicate that early visual processing deficits in schizophrenia are apparent during emotion processing but, depending on symptom severity, these deficits can be restored by presenting concurrent emotionally congruent sounds.     

Neural correlates of formal thought disorder: An activation likelihood estimation meta‐analysis

Formal thought disorder (FTD) refers to a psychopathological dimension characterized by disorganized and incoherent speech. Whether symptoms of FTD arise from aberrant processing in language‐related regions or more general cognitive networks, however, remains debated. Here, we addressed this question by a quantitative meta‐analysis of published functional neuroimaging studies on FTD. The revised Activation Likelihood Estimation (ALE) algorithm was used to test for convergent aberrant activation changes in 18 studies (30 experiments) investigating FTD, of which 17 studies comprised schizophrenia patients and one study healthy subjects administered to S‐ketamine. Additionally, we analyzed task‐dependent and task‐independent (resting‐state) functional connectivity (FC) of brain regions showing convergence in activation changes. Subsequent functional characterization was performed for the initial clusters and the delineated connectivity networks by reference to the BrainMap database. Consistent activation changes were found in the left superior temporal gyrus (STG) and two regions within the left posterior middle temporal gyrus (p‐MTG), ventrally (vp‐MTG) and dorsally (dp‐MTG). Functional characterization revealed a prominent functional association of ensuing clusters from our ALE meta‐analysis with language and speech processing, as well as auditory perception in STG and with social cognition in dp‐MTG. FC analysis identified task‐dependent and task‐independent networks for all three seed regions, which were mainly related to language and speech processing, but showed additional involvement in higher order cognitive functions. Our findings suggest that FTD is mainly characterized by abnormal activation in brain regions of the left hemisphere that are associated with language and speech processing, but also extend to higher order cognitive functions. Hum Brain Mapp 38:4946–4965, 2017. © 2017 Wiley Periodicals, Inc.     

Impact of triple pelvic osteotomy on contact stress pressure distribution in the hip joint

Purpose

We studied changes of contact stress distribution in the hip joint after Tonnis triple pelvic osteotomy applied in the treatment of dysplasia and hip joint incongruence in adolescents.

Methods

In a group of 75 patients, 54 (72 %) female, who underwent surgery by triple pelvic osteotomy in adolescence for developmental disorder of the hip and avascular necrosis of the femoral head, a three-dimensional hip joint model was used based on the radiography of the pelvis with hips. The following biomechanical parameters were calculated: resultant hip force normalised to body weight (R/Wb), inclination of the resultant hip force (θ−R), the position of the stress pole (θ), peak contact hip stress (Pmax), and peak contact hip stress normalised to body weight (Pmax/Wb). Gait quality was also assessed.

Results

After surgery the Wiberg CE angle was increased by 17.85° (114 %), resultant hip force normalised to body weight (R/Wb) was decreased by 0.107 (3.3 %), the position of the stress pole was shifted medially by 27.59° (63.5 %), and peak contact hip stress normalised to body weight (Pmax/Wb) was decreased by 2249.74 (55.9 %). Waddling gait was reduced from 17 (23.9 %) to four cases (5.6 %). All changes were statistically highly significant (p<0.01).

Conclusions

The effect of Tonnis triple pelvic osteotomy lies in the improvement of stress distribution across the acetabular cartilage of the hip joint, thus slowing down the degenerative damage of the hip joint.     

Unfavorable hip stress distribution after Legg–Calvé–Perthes syndrome: A 25‐year follow‐up of 135 hips

To study the effect of hip and pelvis geometry on development of the hip after Perthes disease, we determined the resultant hip force and contact hip stress distribution in a population of 135 adult hips of patients who had been treated for Perthes disease in childhood. Contra‐lateral hips with no record of disease were taken as the control population. Biomechanical parameters were determined by mathematical models for resultant hip force in one‐legged stance and for contact hip stress, which use as an input the geometrical parameters assessed from anteroposterior radiographs. The mathematical model for stress was upgraded to account for the deviation of the femoral head shape from spherical. No differences were found in resultant hip force and in peak contact hip stress between the hips that were in childhood subject to Perthes disease and the control population, but a considerable (148%) and significant (p < 0.001) difference was found in the contact hip stress gradient index, expressing an unfavorable, steep decrease of contact stress at the lateral acetabular rim. This finding indicates an increased risk of early coxarthritis in hips subject to Perthes disease. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:8–16, 2014.     

Clinically significant symptom change in children with attention‐deficit/hyperactivity disorder: does it correspond with reliable improvement in functioning?

This study examined the relation between clinically significant (CS) change in symptoms of attention‐deficit/hyperactivity disorder (ADHD) and of oppositional defiant disorder (ODD), and reliable change in multiple domains of functioning in children who participated in the Multimodal Treatment Study of Children with ADHD. Children with CS change in symptoms were significantly more likely than children without CS change to have reliable change across five domains of functioning. Interestingly, however, depending on the measure of functioning, 14 to 52% of children who did not achieve CS change in symptoms showed reliable improvement in functional domains. The results have implications for the definition and measurement of CS change in child treatment‐outcome studies. © 2008 Wiley Periodicals, Inc. J Clin Psychol 65:1–18, 2009.     

Single particle adsorbing transfer system

Here we present a novel approach for horizontal transfer of single particles after laser microdissection. The developed technique is a single particle adsorbing system for highly selective and gentle horizontal transfer of microdissected fixed and living material. As mediated via low-pressure technology, the transfer process can be precisely controlled, thus facilitating horizontal particle transfer of any isolated material, e.g. tissue material, single cells or chromosomes, in addition to precise positioning for sample release. This collection method allows one to predefine target positions and enables material transfer without contamination to any planar microchip device. This contamination free transfer is indispensable for novel lab-on-a-chip systems performing nanoscale polymerase chain reaction analyses. Using virtual reaction chamber microdevices, small amounts of microdissected material—as little as one single cell—can be directly transmitted and immediately used for single cell analysis. Daniela Woide and Veronika Mayer contributed equally to this paper.     

Ferritin concentrations in dried serum spots from capillary and venous blood in children in Sri Lanka: a validation study

BACKGROUND: Assessing iron status continues to be challenging in field situations. Spot methods developed for analyzing ferritin from serum or plasma samples that are spotted and dried on filter paper have been shown to provide reliable and accurate iron-status assessments. However, the spot methods are based on samples from venous serum or plasma and have not been evaluated in field settings. OBJECTIVE: We evaluated the validity of analyzing ferritin to assess iron status by using venous and capillary dried-serum-spot (DSS) samples by the spot method compared with using serum ferritin by the traditional method in a field setting. DESIGN: Venous and capillary blood was obtained from healthy schoolchildren (n = 100; +/- SD age: 8.9 +/- 0.3 y) in Colombo, Sri Lanka. To prepare DSS samples, we aliquoted precisely 20 microL serum per spot on filter paper, air-dried the spots, and placed them in airtight plastic bags until analysis by the spot ferritin method with the use of cellulase from Trichoderma reesei at 2 wk after collection. Venous serum (100 microL) was frozen until ferritin determination by traditional radioimmunoassay. RESULTS: Venous and capillary DSS ferritin values correlated strongly with traditional serum ferritin values (r = 0.88 and 0.86, respectively; P = 0.0001). The geometric means (+/- 1 SD) for venous and capillary DSS ferritin and traditional ferritin were 26.9 (15.3-47.4), 33.9 (20.9-54.8), and 33.1 (18.6-58.8) microg/L, respectively, and were not significantly different. Venous and capillary DSS methods on average (+/- SD) yielded ferritin values that were 5.8 +/- 10.1 microg/L lower and 0.1 +/- 9.4 microg/L higher, respectively, than serum ferritin values obtained with the traditional method. CONCLUSIONS: Capillary and venous DSS methods for analyzing ferritin provide accurate tools for assessing iron status. Furthermore, capillary DSS ferritin is a practical means of detecting iron deficiency in field settings.