Side difference in the hip and knee joint moments during sit-to-stand and stand-to-sit tasks in individuals with hemiparesis.

BACKGROUND: No study has reported the differences between sides in the net muscular moment of lower limbs of subjects with hemiparesis during sit-to-stand and stand-to-sit tasks in various foot positions. Moreover, the asymmetry of lower-joint moments has not yet been related to muscular weakness of the lower limbs in this population. METHODS: A convenience sample of 12 individuals (mean age (standard deviation): 49.7 (9.0) years) with chronic hemiparesis due to stroke were asked to stand up and sit down at their natural speed in four foot positions. The joint moments at the hip and knee on both sides during the tasks were estimated with an inverse dynamic approach while the dynamic concentric strength in extension at the hip and knee was assessed with a Biodex dynamometric system. Statistical analyses (paired t-tests and ANOVAs) were used to assess the effects of sides and foot position factor on the asymmetry in the hip and knee joint moments. The level of association between muscle weakness and the asymmetry in the joint moments was quantified with Pearson correlation coefficients (r). FINDINGS: At the knee, the extensor moments were significantly lower on the affected side (P<0.05) and were affected by the foot position. At the hip, the moments were not significantly different between sides and were slightly modified by the foot positions. There were also strong correlations (0.70

The effect of foot position and chair height on the asymmetry of vertical forces during sit-to-stand and stand-to-sit tasks in individuals with hemiparesis.

BACKGROUND: The asymmetrical motor pattern of persons with hemiparesis influences the performance of activities that require interactions between the two sides of the body. METHODS: Twelve subjects with a chronic hemiparesis were asked to stand up and sit down at their natural speed in the following foot positions: (1) spontaneous; (2) symmetrical; (3) asymmetrical with the affected foot placed backward; and (4) asymmetrical with the unaffected foot placed backward. Forces were recorded under each foot using two force plates and under each thigh with an instrumented chair. Each foot position was tested at two chair heights corresponding to 100% and 120% of leg length. For each condition, the duration and the asymmetry of loading expressed by the vertical forces were calculated for four different events: onset, transition (forces under feet and thighs), seat-off or seat-on and at the end of the task. FINDINGS: The time to execute the tasks ranged from 2.31 s to 3.69 s with higher values observed for the stand-to-sit task than for the sit-to-stand task. Overall, the asymmetry of vertical forces was greatest in the middle part of the tasks and was not influenced by the chair height. When the subjects were still in contact with the seat, the loading asymmetry originated from a difference between sides at both the thigh and the foot. The asymmetrical foot position with the affected foot backward promoted loading on the affected side during both tasks. Interpretation. This study shows that loading asymmetry was present before seat-off and after seat-on in sit-to-stand and stand-to-sit tasks, respectively. It shows that positioning the affected foot behind reduces the asymmetry whereas positioning the unaffected foot behind increases the asymmetry. Foot position should be taken into consideration when clinicians assess or train for these mobility tasks.

Effects of repeated distension arthrographies combined with a home exercise program among adults with idiopathic adhesive capsulitis of the shoulder.

OBJECTIVE: The purpose of this study was to measure the effect of repeated distension arthrographies combined with a home exercise program on impairments and disability of the upper limb in subjects with adhesive capsulitis of the shoulder. DESIGN: A total of 15 subjects with idiopathic adhesive capsulitis participated in the study. Intervention consisted of three distension arthrographies with steroid, done at 3-wk intervals, and a home exercise program. The repeated-measures design included five clinical evaluations with disability, pain, range of motion, and pain-free static strength outcomes. Two evaluations done before the first arthrography verified the stability of the condition. RESULTS: There was a significant improvement of all outcomes at the end of intervention. The greatest effects occurred after the first distension arthrography. After the second, less marked, albeit significant, changes were observed in three motions of the shoulder and in the pain level. After the third distension arthrography, very small changes were noted. A comparison between sides revealed incomplete recovery of the range of motion on the affected side. CONCLUSIONS: These findings showed that two distension arthrographies with steroid combined with a home exercise program reduce shoulder disability and impairments. Adding a third distension arthrography does not seem to provide any further benefit.

The Drosophila poly(A) binding protein-interacting protein, dPaip2, is a novel effector of cell growth.

The 3' poly(A) tail of eukaryotic mRNAs and the poly(A) binding protein (PABP) play important roles in the regulation of translation. Recently, a human PABP-interacting protein, Paip2, which disrupts the PABP-poly(A) interaction and consequently inhibits translation, was described. To gain insight into the biological role of Paip2, we studied the Drosophila melanogaster Paip2 (dPaip2). dPaip2 is the bona fide human Paip2 homologue, as it interacts with dPABP, inhibits binding of dPABP to the mRNA poly(A) tail, and reduces translation of a reporter mRNA by approximately 80% in an S2 cell-free translation extract. Ectopic overexpression of dPaip2 in Drosophila wings and wing discs results in a size reduction phenotype, which is due to a decrease in cell number. Clones of cells overexpressing dPaip2 in wing discs also contain fewer cells than controls. This phenotype can be explained by a primary effect on cell growth. Indeed, overexpression of dPaip2 in postreplicative tissues inhibits growth, inasmuch as it reduces ommatidia size in eyes and cell size in the larval fat body. We conclude that dPaip2 inhibits cell growth primarily by inhibiting protein synthesis.

Paip1 interacts with poly(A) binding protein through two independent binding motifs.

The 3' poly(A) tail of eukaryotic mRNAs plays an important role in the regulation of translation. The poly(A) binding protein (PABP) interacts with eukaryotic initiation factor 4G (eIF4G), a component of the eIF4F complex, which binds to the 5' cap structure. The PABP-eIF4G interaction brings about the circularization of the mRNA by joining its 5' and 3' termini, thereby stimulating mRNA translation. The activity of PABP is regulated by two interacting proteins, Paip1 and Paip2. To study the mechanism of the Paip1-PABP interaction, far-Western, glutathione S-transferase pull-down, and surface plasmon resonance experiments were performed. Paip1 contains two binding sites for PABP, PAM1 and PAM2 (for PABP-interacting motifs 1 and 2). PAM2 consists of a 15-amino-acid stretch residing in the N terminus, and PAM1 encompasses a larger C-terminal acidic-amino-acid-rich region. PABP also contains two Paip1 binding sites, one located in RNA recognition motifs 1 and 2 and the other located in the C-terminal domain. Paip1 binds to PABP with a 1:1 stoichiometry and an apparent K(d) of 1.9 nM.