Red cell membrane stiffness in iron deficiency

The purpose of this study was to characterize red blood cell (RBC) deformability by iron deficiency. We measured RBC deformability to ektacytometry, a laser diffraction method for determining the elongation of suspended red cells subjected to shear stress. Isotonic deformability of RBC from iron-deficient human subjects was consistently and significantly lower than that of normal controls. In groups of rats with severe and moderate dietary iron deficiency, RBC deformability was also reduced in proportion to the severity of iron deficiency. At any given shear stress value, deformability of resealed RBC ghosts from both iron-deficient humans and rats was lower than that of control ghosts. However, increase of applied shear stress resulted in progressive increase in ghost deformation, indicating that ghost deformability was primarily limited by membrane stiffness rather than by reduced surface area-to-volume ratio. This was consistent with the finding that iron-deficient cells had a normal membrane surface area. In addition, the reduced mean corpuscular hemoglobin concentration (MCHC) and buoyant density of the iron-deficient rat cells indicated that a high hemoglobin concentration was not responsible for impaired whole cell deformability. Biochemical studies of rat RBC showed increased membrane lipid and protein crosslinking and reduced intracellular cation content, findings that are consistent with in vivo peroxidative damage. RBC from iron-deficient rats incubated in vitro with hydrogen peroxide showed increased generation of malonyldialdehyde, an end-product of lipid peroxidation, compared to control RBC. Taken together, these findings suggest that peroxidation could contribute in part to increased membrane stiffness in iron- deficient RBC. This reduced membrane deformability may in turn contribute to impaired red cell survival in iron deficiency.     

A Further Investigation of Goal-Directed Intention Understanding in Young Children with Autism Spectrum Disorders

Findings from research investigating goal-directed intention understanding in children with autism spectrum disorders (ASD) have been equivocal, in part because of the varying methodologies used across studies. This study compares both object-oriented and social-communicatively cued goal-directed intention understanding in children with ASD and typically-developing children. Relative to matched controls, children with ASD did not exhibit deficits in object-oriented intention understanding. While children with ASD also demonstrated the ability to understand intention when cued by social-communication indicators, typically-developing children differentiated between intentional and unintentional acts at a significantly greater level. Group differences in performance were eliminated if only trials in which children attended to the experimenter’s face were considered. Results suggest that children with ASD have intact object-oriented intention understanding abilities, and are able to use social-communicative cues to understand intention. However, their ability to demonstrate social-communicatively cued intention understanding is limited by a lack of attention to relevant social-communicative information.     

四肢关节专用低场强MRI评估对膝关节损伤的诊断价值

目的：分析四肢关节专用低场强MRI诊断膝关节损伤的临床应用价值。 方法：于2004-12/2005-10解放军总医院全军骨科研究所收治经手术、关节镜检查或临床证实的膝关节损伤患者40例（43个膝关节）。应用Atorscan0.2T永磁型四肢关节专用低场强磁共振机,对膝关节损伤的MRI表现进行分析。 结果：四肢关节专用低场强MRI对半月板、前交叉韧带、骨挫伤等均可作出正确诊断。 结论：四肢关节专用低场强MRI对膝关节损伤的综合诊断具有重要意义,是膝关节损伤较理想的一种非创伤性检查方法。     

Association between genes on chromosome 4p16 and non-syndromic oral clefts in four populations

Isolated cleft lip with or without cleft palate and cleft palate are among the most common human birth defects. Several candidate gene studies on MSX1 have shown significant association between markers in MSX1 and risk of oral clefts, and re-sequencing studies have identified multiple mutations in MSX1 in a small minority of cases, which may account for 1–2% of all isolated oral clefts cases. We explored the 2-Mb region around MSX1, using a marker map of 393 single nucleotide polymorphisms (SNPs) in 297 cleft lip, with or without cleft palate, case–parent trios and 84 cleft palate trios from Maryland, Taiwan, Singapore, and Korea. Both individual markers and haplotypes of two to five SNPs showed several regions yielding statistical evidence for linkage and disequilibrium. Two genes (STK32B and EVC) yielded consistent evidence from cleft lip, with or without cleft palate, trios in all four populations. These two genes plus EVC2 also yielded suggestive evidence for linkage and disequilibrium among cleft palate trios. This analysis suggests that several genes, not just MSX1, in this region may influence risk of oral clefts.     

Tibiofemoral Joint Positioning for the Valgus Stress Test

Context:

Recommendations on the positioning of the tibiofemoral joint during a valgus stress test to optimize isolation of the medial collateral ligament (MCL) from other medial joint structures vary in the literature. If a specific amount of flexion could be identified as optimally isolating the MCL, teaching and using the technique would be more consistent in clinical application.

Objective:

To determine the angle of tibiofemoral joint flexion between 0° and 20° that causes a difference in the slope of the force-strain line when measuring the resistance to a valgus force applied to the joint.

Design:

Cross-sectional study.

Setting:

University research laboratory.

Patients or Other Participants:

Twelve healthy volunteers (6 men, 6 women: age  =  26.4 ± 5.6 years, height  =  170.9 ± 8.4 cm, mass  =  75.01 ± 14.6 kg).

Intervention(s):

Using an arthrometer, we applied a valgus force, over a range of 60 N, to the tibiofemoral joint in 0°, 5°, 10°, 15°, and 20° of flexion.

Main Outcome Measure(s):

Force-strain measurements were obtained for 5 positions of tibiofemoral joint flexion.

Results:

As knee flexion angle increased, slope values decreased (F_4,44  =  17.6, P < .001). The slope at full extension was not different from that at 5° of flexion, but it was different from the slopes at angles greater than 10° of flexion. Similarly, the slope at 5° of flexion was not different from that at 10° of flexion, but it was different from the slopes at 15° and 20° of flexion. Further, the slope at 10° of flexion was not different from that at 15° or 20° of flexion. Finally, the slope at 15° of flexion was not different from that at 20° of flexion.

Conclusions:

When performing the manual valgus stress test, the clinician should fully extend the tibiofemoral joint or flex it to 5° to assess all resisting medial tibiofemoral joint structures and again at 15° to 20° of joint flexion to further assess the MCL.     

Lumbopelvic joint manipulation and quadriceps activation of people with patellofemoral pain syndrome

Context:

Quadriceps weakness and inhibition are impairments associated with patellofemoral pain syndrome (PFPS). Lumbopelvic joint manipulation has been shown to improve quadriceps force output and inhibition, but the duration of the effect is unknown.

Objective:

To determine whether quadriceps strength and activation are increased and maintained for 1 hour after high-grade or low-grade joint mobilization or manipulation applied at the lumbopelvic region in people with PFPS.

Design:

Randomized controlled clinical trial.

Setting:

University laboratory.

Patients or Other Participants:

Forty-eight people with PFPS (age = 24.6±8.9 years, height = 174.3 ± 11.2 cm, mass = 78.4 ± 16.8 kg) participated.

Intervention(s):

Participants were randomized to 1 of 3 groups: lumbopelvic joint manipulation (grade V), side-lying lumbar midrange flexion and extension passive range of motion (grade II) for 1 minute, or prone extension on the elbows for 3 minutes.

Main Outcome Measure(s):

Quadriceps force and activation were measured using the burst superimposition technique during a seated isometric knee extension task. A 2-way repeated-measures analysis of variance was performed to compare changes in quadriceps force and activation among groups over time (before intervention and at 0, 20, 40, and 60 minutes after intervention).

Results:

We found no differences in quadriceps force output (F_5,33,101,18 = 0.65, P = .67) or central activation ratio (F_4.84,92.03 = 0.38, P= .86) values among groups after intervention. When groups were pooled, we found differences across time for quadriceps force (F_2.66,_101.18 = 5.03, P = .004) and activation (F_2.42,92.03 = 3.85, P = .02). Quadriceps force was not different at 0 minutes after intervention (t₄₀ = 1.68, P = .10), but it decreased at 20 (t₄₀ = 2.16, P = .04), 40 (t₄₀ = 2.87, P = .01) and 60 (t₄₀ = 3.04, P = .004) minutes after intervention. All groups demonstrated decreased quadriceps activation at 0 minutes after intervention (t₄₀ = 4.17, P <.001), but subsequent measures were not different from preintervention levels (t₄₀ range, 1.53–1.83, P >.09).

Conclusions:

Interventions directed at the lumbopelvic region did not have immediate effects on quadriceps force output or activation. Muscle fatigue might have contributed to decreased force output and activation over 1 hour of testing.     

Intervention Fidelity: An Essential Component for Understanding ASD Parent Training Research and Practice

Previous research has explored the efficacy and effectiveness of autism spectrum disorder (ASD) parent training interventions. Recent trials of such programs have not replicated earlier compelling outcomes, yet the reasons for the failure of such programs to produce desired effects are unclear. The purpose of the current article is to discuss the role of intervention fidelity in elucidating the relationships between a parent training program, the implementation and sustainability of an intervention, and important child outcomes. The article will discuss the importance of assessing intervention fidelity for the identification and successful use of effective treatment strategies and will propose an integrative conceptual framework for approaching the study and evaluation of intervention fidelity with respect to ASD parent training programs.